as Pseudonym said, the AC adapter is universal. all you need is the plug converter. you won't need the voltage converter, which is much more expensive.
if you wanted to be 100% legal, you will need to declare your laptop at the customs upon return to U.K. and pay import duty on it. it may or may not be higher than the local VAT.
applecare is international, afaik, but better make sure anyway.
another consideration: your credit card company will give you an exchange rate that will be pretty close to the wholesale market rate, but not quite. that may add somewhat to the overall price.
if you wanted to be 100% legal, you will need to declare your laptop at the customs upon return to U.K. and pay import duty on it. it may or may not be higher than the local VAT.
applecare is international, afaik, but better make sure anyway.
another consideration: your credit card company will give you an exchange rate that will be pretty close to the wholesale market rate, but not quite. that may add somewhat to the overall price.