well the costs of moving house in the UK are quite high.
stamp duty: 1% on £200,000 http://www.hmrc.gov.uk/so/rates/index.htm
Conveyancing/Solicitors fees: ??? depends but I would allow at least £2000 but could be less depending on who you get to do it.
House survey: ??? several hundred pounds.
If you take a loan/mortgage for the house, you will also have to pay for a survey by the lendor. This is a basic survey to check the house isn't falling down etc. But they nearly always find some work that needs doing unless its a new property, and that work has to be carried out as a condition of the loan so there is cost involved.
Moving costs from Italy.
£200,000 won't buy very much in sussex or surrey. A very small house if you are lucky otherwise a flat. They are very expensive areas to live.
Then yearly you have to pay Council Tax which would be at least £1000.00 and probably more in the area you are planning on.
Commuting costs to London are very high. You should check with British Rail website. And if you have to leave car at station they will charge a lot for that.
Then fuel costs are very high because of very high fuel tax. Currently £1.30 a litre and rising fast.
VAT 17.5% on almost everything.