I go to spain every year and I met this girl rachel and every year I went I met her she was like a big sister to me and one day she moved to england how do I get in thouch

The ONLY way you are going to find her is if you by luck... find someone that happened to know her. If you had her last name too you would stand a much better chance, or in addition knew her home town.

Odd that she was like a big sister but you never knew her last name?