Credit files at the credit agencies are massive (as you might imagine) the largest agencies deal internationally - i.e. 100's of millions of people.
If you really want to update your credit record you do need something concrete from the UK court in terms of a Court Order to say that the entry was wrong (for whatever reason e.g. the debt order was overturned - NOT that the debt was seviced - that won't work half as much). Even then you will struggle to get that changed on the computer records with multiple agencies without massive effort. Don't give up - but you will need to prove that what they recorded was wrong.
Also concentrate on improving your credit record - now I couldn't possibly say how that might be done, as I actually disapprove
However if you are confident of your self control - borrowing a lot of money on a lot of credit cards and regularly paying off quickly (avoiding any interest payments) certainly used to work. It might not any more - the algorithms may have changed.
It is strange but - but the more you borrow - BUT PAY OFF under ther terms of the agreement the better your credit rating gets. Used to be that way anyway - think it still is - and I can see why - but don't pay any stupid interest rate charges in doing so (that is easy to miss - one full re-payment missed your interest rate will be extortionate - that is where they expect their profits to come from).
Note: I am not legally qualified, just been around a few blocks. The sorry cynic.