It's pretty difficult to be able to give you a specific answer to this without really knowing the likely contents to the personal statement you refer to.
However as general advice I would suggest the following -
- Avoid extensive use of American buzz words, slang, expressions, sayings and particularly in vogue 'management speak'. These are not likely to be looked upon particularly favourably by an English University, nor will the specific meaning of the unfamiliar expressions be immediately apparent.
There is quite a movement and dislike of this kind of language and the increasing amount of Americanisation pervading the English language in this country (England). There's been quite a lot of press about this recently with regards to the fairly large number of 'new' words and 'sayings' entering the language. A lot of people just don't like it.
Write in clear, concise, grammatically correct, correctly spelt (even if it must be American spelling) English and avoid unnecessary 'fluff' and 'flannel'. In other words don't write several paragraphs when one sentence will do. Sometimes less is more.