Colin, I suggest to reach out to Peter Havlik with a PM (username PETERH) and the De Tomaso Drivers Club UK. Peter has amassed a lot of information and compiled the registry for 9,000 series cars. VIN# 9228 would be consistent with a 1982 production / registration. Drop me a PM and I can put you in touch with some of the Brit owners who may know of the car.
The Provamo photos show a RHD GT5 (no running boards?) that is quite heavily modified with carbon fiber and a mix of Euro and English gauges (km/h speedo, 'fuel, Amps' gauges and 'press olio, Aqua C'), no way of knowing from the photos for sure whether it left the factory as a RHD, unless the owner has some historical documentation, but it is a lot of work to convert one.