1) What is the quality of the reception on those channels I can get likely to be like?
No different to your Krakow experience i'd imagine, with a modern sky box and a 1m dish correctly alligned the reception quality is excellent.
2) Apart from BBC and ITV (which i understand you can't get without a massive dish), are there any other major channels that won't be available?
E4 but there is a way to get the Irish E4 instead.
3) If i subscribe to Sky Sports and movies, will I get them?! Or will I be wasting my money!?
Yes you can get them and it really depends on your taste as to whether you are wasting your money.