Update : (Entwood on Janines machine

)
Read the codes .. none showing on Engine, but 3 on transmission ... forgot to write them down ..

Cleared all the codes, then tried to start it, very reluctant to start, turning over and attempting to fire, eventually caught on 3, quickly went to all 4. Engine has not been started since it broke down mid-december. No faults showing, the GS500 won't do live data on this one for some reason.. so a bit stumped.
Vehicle is SORNed so couldn't drive it .. but in moving small distances on the drive I found that passing through positions 1 & 2 on the auto selector ALL the lights on the selector unit flash randomly .. ok at all other positions .... makes me wonder if the selector needs a damned good clean ??.
Ran it for 30 minutes .. all seemed fine .. stopped and started 6 times without any problems.
Other problems, unrelated .... ABS ECU is FUBAR ... ABS light on /no speedo (apparently sometimes the speedo works and the light goes out ...

Coolant level sensor knacked .. low level warning but fluid level fine
A few other minor odds and sods but for what they paid its a bargain....

My recommendation is to leave it overnight to get cold again then try and start it .. if it starts OK having not been driven it sort of discounts cam- crank - sensors.
Then, when happy, and after cleaning the selector, try driving around the block a few times and see if the gearbox faults come back.
Any thoughts gratefully accepted.