Congrats.
I lived in England for a while a couple of years ago, and had a great time.
One bit of car-related advice:
The UK has MUCH different insurance laws than we do. For example, you get 30 days to drop any new insurance policy, but after that they will charge you a BIG fee to drop. Also their rates are super high for inexperienced drivers.
See if you can get a letter from your US insurance agent before you move that states how many years you have been insured and how long you have been accident free. Then make sure your UK agency will accept that before you sign up.
Not knowing how it worked I ended up with a company that would not accept the letter my US agency sent them, so they jacked my rate up like 6x, and then wanted me to pay them something like $2k to drop the insurance even after I sold my car. Very frustrating.
Other than that I really liked England (I lived in Enstone, near Oxford).
A few other things I noticed that were different to me:
They take 2 tea breaks a day, and they are mandatory, working through them will piss off everyone ( I don't like tea, but the English way with milk and sugar isn't bad).
If you get a dog, you can bring him to the pub with you! (provided you train him well)
In winter it will be 40*F, but you will want to dress for 0*, because the humidity makes it so much colder, and they keep it cooler inside than we do. Bring underarmor.
Roundabouts are great in a country where they know how to use them.
Customer service is much less than in the US. Stores have shorter hours and not everyone has return policies and stuff like that. Not a big deal when you get used to it, but can be a surprise if you new cell phone doesn't work or something.
Stuff is quite a bit more expensive, so bring your high dollar items and nicer clothes with you.
Most places will not have a garage, so be prepared for that. Also it is much harder to get good tools compared to the US. Halfords is OK, but not near as good as sears, and I don't know if there is something like the Snap-On guy or not.
Each geographical region will have a couple of local beers, and most all pubs in the area will carry that and not much else selection wise. Still English beer is really good once you get used to it.
Vintage cars! Vintage is all the rage over there, and there is a huge community of people restoring/showing/racing cars from about 1910s-1940s. If you want something cool and different, you might want to get into that group...
Anyway, have a good time. I sometimes wish my wife and I had decided to move to England long-term when we had the offer.