Hey thanks for the replies everyone.
So basically, all it is is a name change. So this means there's no change to your rating and your records aren't kind of 'lost' due to being under a different identity. Is that about the size of it?
Yes you are right, my question was simply about the rating itself, but that was because I assumed under the gender discrimination laws that your old identity would be hidden. The credit people have no reason to know your tran's status.
This DOES concern me, as of course it means people making money decisions on your behalf would have the opportunity to discriminate against you if they were tran's phobic or whatever (and to be fair a lot of what I read online is actually due to lack of education on the subject and these people will probably not be educated on it and it's not like you can explain it to them like you can your family and friends - even then it's hard for some).
However, given the choice of having my rating lost or become disjointed in some way and having people see my old name (girly so would give it away), I'd rather go with keeping the rating. I was hoping to achieve both the rating and my privacy on the matter though, but oh well.
Again, thanks everyone for your help

Steve