As he prefers to use bank transfer and as far as he is reliable, you should use bank rather than third party money transfer.
You did not mention about your residential country, US or UK? -- Does not matter citizenship
Which bank do you use? - US bank or British Bank?
Which currency do you use -- USD or GBP
Do you need to convert FX?
Each of that seriously effect your commission / conversion rate

Hi everybody! I am new in this forum and this is my first post.
I found one guy who can sell me some BTC, and he prefer to use bank transfer.
The problems in, that i citizen of U.S. while he is from UK.
I understand that i need to make international wire transfer, but i dont know how to do this one.
some people suggests me to use xe.com.
I would be really appreciate, if you can tell me how better send money from US to UK using bank account?