If he's the same Bill yates I'm thinking of he worked as a NavData Analyst with SITA in Isleworth early / mid 90's. Lived in the Ascot area. Perhaps a call to SITA personnel would help as he was member of the Pension Fund and well retired by now.
Always into DIY as I recall and think he was intent on renovating his house in order to sell, so SITA probably best avenue.