As others have said, as a general rule expect everything to be more expensive than you’re used to, and then some. This is especially true of the major cities (London) but the rest of England is still quite expensive. This is the land of massive and crippling direct and indirect taxation. Which would be fine if it resulted in superb public services, but instead the tax is generally wasted on political games and bureaucratic madness.
If you pay UK income taxes, a large chunk of your earnings will go in income tax and National Insurance (NI) which is… just another name for more tax. If you want to own a TV or anything capable of receiving a wireless transmission, you must buy a TV licence… which is just another name for another tax. Most things you buy have Value Added Tax or VAT slapped on at 17.5%. If you want to own and run a car, it gets insane. You have to pay for the car (at prices about 20% higher than the rest of Europe), the insurance (diablically expensive) and the road tax (hey! Another tax!). Petrol is more expensive here than anywhere else. If you have the audacity to want to park your car anywhere near a town or city centre, you’ll pay a lot for the privilege. If you fail to understand the Byzantine rules and regulations about parking, and make a simple honest mistake, expect fines of - for example - £80 ($128) for the sin of parking where you shouldn’t have, and maybe £160 ($256) to get your car back if it was towed away. No arguments, no appeal. You pay up or they keep your car. Plus if you go near central London there’s the Congestion Charge (another tax!) to pay as well.
When calculating the costs of running a car, bear in mind that there is a very high chance that your car will be broken into or stolen (mine has been ‘done over’ four times in the last two years). Car-related crime is an epidemic over here, and the police have given up because there’s nothing they can do about it.
While you’re getting used to the generally higher prices, learn to expect lower quality as well. If you eat out, you’ll be dismayed at the kind of sludgy slop that passes for ‘good food’ in England, and how poorly it is served up. In general, in retail and service establishments, expect to be treated as an unwanted contamination of the salesperson’s free time. You will often find yourself staring at the indifferent and unresponsive backs of the people who are, in theory, there to serve you.
My advice: get yourself an accountant as soon as you arrive. Go through your position thoroughly. A good accountant can save you a huge amount of money, and British tax laws are too cumbersome, absurd, archaic and complex for anyone but a trained professional to deal with.