When accelerating moderately hard this morning, the gear box wouldn't shift: it seemed as though it was going back and forth between gears. There was a brief "restricted performance' alarm. The fault persisted (minus the restricted performance alarm) for a few minutes then returned after another few miles.
I have previously experienced a hard shift into reverse when the engine was cold, but this seems to have reduced (or I got used to it).
Does anyone have any thoughts or further questions?

 

I don't know if you have had the fluid level checked, but I would start there before digging into the switches and linkage.

 

Hi Richard, I recently had restricted performance due transmission on XKR, turned out to be small hose vac/pressure not sure back of the engine high near fire wall. Re affixed with nylon tie and all good. Had to reset the computer with Obd reader tho.
I have 2002 Daimler in Hua Hin, just had super major service in BKK inc tensioners chains and transmission fluid change, I think your model will have a sealed for life tranny??. if you can get plugged into a reader and give me the fault code may be able to tell you what the problem is.

 

Thanks for the comments and offer of help. I don't have access to a code reader, any information about which one to buy would be useful...? I've done a bit more research on the problem and hope it might turn out to be low fluid level so have ordered a service kit from Jaguar Heritage Parts and aim to change the oil next week... Fingers crossed! I really enjoy the rarity of Jaguar driving here in Thailand but sometimes find it a struggle keeping the car on the road. Also finding Benzine when on a road trip makes life more interesting than comfortable at times... Best wishes