It never ceases to amaze me what folks are willing to put a puppy thru, for a certain cosmetic look, as well.
A long transport, flight, and presumably some sort of quarantine, all at the critical socialization window and first fear period in that young bit's life.
France to England is about 1 hour, also you can take your dog on Eurostar as long as it remains in the car, so get a boot (trunk) gate and put the pup in there, its the equivalent to being in a cage for an hour... Eurostar is pretty seamless
also you can take a dog on dover-calais on p&o apparently as long as its in a cardboard transport box (baring in mind its a puppy so its not very large) so thats another 1 hour journey this time on a boat which may be a bit more stressful but you can stay with the dog the whole time!
With a pet passport quarantine is quite short i believe, dog must have had rabies shots and is allowed to travel to and from ANY EU country
JUST READ THAT PET PASSPORT = NO QUARANTINE!
So really France to UK is quite minor
Its not like a 5 hour flight then months in quarantine, France is probably the easiest and fastest country to import from