Noise & heat are not an issue. Running 240v in UK just to clarify it's not stolen electricity or anything illegal.
As phil said a S7 would be good in your situation. I would look to try to get one for a decent deal, which is a little harder in UK (VAT and such seems to raise the price of your miner sell's even on used). Make sure when buying to compare prices to S9 as you should be getting a decent amount cheaper then it as S7's are not near as efficient.
Also with 240 you can use server PSU's which will save some money. I personally like the recommended APW3's and have had no issues with them, but some prefer others.