I've gone for the service early option - as its precisely what we did before going to the South of France. Basically same situation as yourself - 2,500 miles in France, Service says 3,500 to go.
However I had the car serviced at least a week before travel - to account for any dealer issues (turned out I had a few so a good move).
I'd also add that I had the headlamps converted to LHD, (Bi Xenon) - and they converted them back on return. I can promise they still aren't right - the self leveling adjustment doesn't work (lights dip down and up on turn on) - this is due to be sorted by my pet dealer shortly.
Aggro - but I'd rather know the car had been looked over.
Clarky.