Reading through my guess is the fluid draining to the sump - I use mine daily but on start up always let it idle for a minute or so. Presumably if used regularly it doesn't do it

My TD6 went through a phase of being slow to pull away after standing for 24 hours or so. I had to leave it ticking over for 30 seconds or so before it would pull away. If I put it into manual it would drive away straight away though. Never did find out the cause, although I suspect it was gearbox fluid draining back into the sump after standing for a while. No longer FF owner but still interested. Present car Jaguar XE
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Previous car Td6 SE
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Previous LR- Disco 300TDi Auto

cool, thanks all, puts my mind at ease, it runs great once it goes  09 TDV8 Westminster, Mariana Black, Rear seat entertainment, hatch bag and 2 slobbery mutts