I brought a dog over from Germany last year, as Yosemite Sam says European pet passport - in your name and address, all relevant veterinary checks done, from recollection it’s a 24-72 hours time frame prior to entering the UK for worming and has to be done and stamped in the passport by a vet. The rabies I think has a booster but either way it can’t travel until15 weeks old so I returned on that day by ferry.
I took the Dover to Calais ferry as it was the shortest crossing for the dog and paid the £18 for the pet lounge where you get complementary teas/coffees/juice so pretty good. If you travel by overnight ferries you have to put the dog into a kennel and don’t get to see it till you get off which isn’t the best for the pup.
When you turn up at the ferry port they check your paperwork and get you to scan the dog and check it against the passport and give you a sticker for the window. When I got off in U.K. there was no further checks and off I went on the long drive home. If you drive, from my experience once your in Europe, whatever Google maps says time wise you’ll find it probably takes a couple of hours longer. If you get he flexifare you can turn up early (or late) and just roll onto the next ferry. We were early so got back on the earlier crossing which was handy.
I looked into flying and had it arranged, or thought I did till Lufthansa changed their mind having said they would and then turned round and only took pets to London (perhaps to do with certain airports accepting animals) which wasn’t any use for me but if you can fly it’s probably cheaper and less hassle in the long run.
With that in mind unless the dog and crate combined is under 10kg (from memory) it goes into the hold. If flying is an option for you I’d pick that over driving, I had arranged and air approved crate on Amazon to be delivered to the breeder which cost about £100 then was going to be £150 if Lufthansa was going to take the dog in the hold. Think pup in a crate on the seat next to you with stupidly small dimensions was £65 but every carrier will dream up its own price and reasons to do or not to do.