Guy qualified from The Royal London Hospital in 1980. He worked in pioneering preventive dental practice in London and Oxford before coming to Diamond House in 1986. He has established the best principles of preventive care and has encouraged the use of minimally invasive dentistry using the best materials and techniques.

He has carried out research in dental pain control and been attached to the Medical Engineering Unit of The University of Oxford.
He acts as an advisor to pharmaceutical companies and as a general dental practice expert to legal professionals.
He lives in Oxford with his wife and two daughters. His interests include sailing and walking.