Your Team
Vassilis Antonas, Founder, Diploma Director
Vassilis Antonas, Founder, Diploma Director
Executive Coach, Psychotherapist, Organisational Development Consultant and Course Director of Impact’s Diploma (AADCT), globally the first Coaching Training to receive Accreditation from the Association for Coaching. Vassilis is the author of Coaching for Impact: The Evolution of Leadership, published by Routledge in 2017.
He has consulted for over 100 Greek and Multinational companies, delivering tens of thousands of consultation hours to leaders from all functions and industries. From 1998 to 2001, he worked for the British NHS and served as Clinical Director for CAP London from 2001 to 2006, at which point he returned to Greece and founded Impact. His vision is to craft the circumstances for pursuing excellence for individuals and organisations: Directly, by offering Executive Coaching and Organisational Development services and indirectly through the Diploma, authoring and keynote speech deliveries.
Vassilis is also a published songwriter, a martial arts instructor, a free diver, former motorsport driver and devoted world traveller; as well as a member of the AC’s Accreditation Committee.
Tereza Venetsanou, Principal Consultant
Her passion for skill development and the empowerment of individuals and teams has emerged through a longstanding career in leading companies such as Vodafone, Microsoft, and Wind, where she spearheaded initiatives that resulted in double-digit revenue growth and significant market development. As Director of Strategy at Universal Coaching Alliance and Principal Consultant at Impact, she leads strategic initiatives, designs, and implements innovative leadership and organisational development programs, contributing to the shaping of sustainable and effective business practices.
With over 3,000 hours of coaching experience and expertise in crisis management, skill redesign, and strategic development, she delivers substantial value and actionable solutions to her clients. She holds an MSc in Integrative Psychotherapy from the University of Derby, is a Certified Master Executive Coach, and has a Diploma in Executive Coaching and Organisational Development. She is also a Certified Master Practitioner in NLP and holds an MA in Marketing from London Metropolitan University.
Her workshops blend theoretical knowledge with experiential practice, drawing from established models such as GROW, PRAID, and the person-centered approach. Emphasizing the creation of a safe environment, she helps participants develop leadership skills, enhance performance, and gain strategies for personal and professional growth.
With a combination of deep knowledge, practical experience, and a human-centered approach, her workshops are a valuable tool for those seeking to grow and succeed in the modern business environment.
Tereza is a 2019 Diploma Alumna.
Dr George Diakonikolaou, Associate, Project Management
George Diakonikolaou is the Managing Director of “Project Management Coach” LTD, delivering services to business clients in the fields of Project Management, Leadership, Coaching and Organisational Development. His clients include companies such as Cosmote, Romtelecom, Vestas, ENEL, EDF etc. George is a visiting Faculty, teaching Project Management in the International MBA in Athens and Brunel Business School, MBA in London as well as Bradford Business School. He has received his First Degree in Electrical Engineering and Computer Science in National Technical University of Athens and his M.Sc. and Ph.D. in Computer Science from University of Manchester Institute of Science and Technology.
George is the co-founder of the Greek Chapter of the Project Management Institute, a Certified Project Management Professional and a founding member of the Hellenic Coaching Association. He is also an NLP Trainer and Master Practitioner of NLP & Time Line Therapy®, a Master Practitioner of Hypnosis and an NLP Master Coach.
Currently, George is experimenting with the integration of Coaching, Organisational Development and Project Management in a field that he likes to refer as “Project Coaching”, an integrated model that achieves groundbreaking results in Strategic Projects, Programs & Portfolios, and executive teams’ performance.
George is a 2010 Diploma Alumnus.
Anna Florou, Associate, Search
Anna began her career as an auditor with one of the big four accounting firms, progressing to financial consulting with expertise in business evaluations and budget creation. Initially dedicated to numbers, she soon discovered her passion for HR Management, leading her to focus on consulting people and driving organizational growth. Currently, she serves as the Office and People Operations Manager at PNOĒ, overseeing operational strategy, talent acquisition, and employee development.
Anna holds a Bachelor in Business Administration from the University of Lausanne’s Faculty of Business and Economics (HEC) and a Bachelor in Hospitality Management from the Glion Institute of Higher Education in Montreux. Fluent in French and English, Anna also communicates proficiently in German, Italian, Spanish, and Korean. Her passions include alpine skiing, CrossFit, hiking, and attending music festivals worldwide.
She is a 2024 Diploma Alumna.
Dimitris I. Chatziapostolou , Associate, Finance Training and Consulting
BA MBA FCCA AICA
Chartered Certified Accountant – Certified Compliance Officer Professional Qualifications Training Expert
Dimitris Chatziapostolou is a chartered certified accountant (FCCA) and a certified compliance officer
(AICA) having accumulated a 20+ year extensive international business experience, out of his 6+ year employment in the big 4 audit firm environment (PwC, Arthur Andersen, Deloitte) and 10 years as a CFO (Sony Music, Metlife Alico, Frigoglass). Employed by multinational organizations while stationed in Europe and SE Asia, has specialized in audit (internal & external), processes and controls, finance & accounting, due diligence & risk management as well as organizational restructuring, in order to achieve performance operational improvement, financial sustainability and growth. Currently employed as a freelance business advisor in Europe, Asia and the Middle East as well as a professional qualifications tutor with more than 8,000 training hours of experience in the areas of audit, financial and risk management.
Sisi Pierri Mougraki, Office Manager
Sisi Pierri brings extensive experience in dynamic administrative roles, underpinned by her current position as an Office Manager. Her role encompasses overseeing daily office operations with responsibilities ranging from managing communications, social media, CRM, and vendor relations to handling complex tasks like coordinating music industry events, property management, and supporting a psychotherapist’s office. She leverages strong organisational and interpersonal skills, while excelling in multitasking within hybrid work settings, and effectively reporting to the Managing Director. This multifaceted role, requiring proactivity, confidentiality, and precision, underscores her adaptability and ability to manage varied tasks smoothly.
She holds a Bachelor in Business Administration (Human Resources and Organisational Behavior) from the American College of Greece. Her passions include snowboard, spearfishing, American billiard (Greek championship), wild mushroom hunting, hiking, dirt bike, martial arts (Greek championship) and music.
She is a mother of two boys.
