Deeley: I'm using 55% of all available credit
OK. I assume that the report has residency and electoral roll data extending back at least 3 years and preferably longer?
Regarding the 55%, hold your horses. There are two conflicting issues here that only you can decide on. Usual advice is to use no more than 30% of available credit so if you close down unused credit you will make that number worse.
On the other hand "settled" accounts are good for your rating and removing unused credit increases the amount of new credit a lender will consider "affordable".
I don't know how big an effect the OD markers are having. Two in a row is not good, possibly will suggest to lenders you are not paying attention or have a temporary problem, and pointless when you had 45% available. Unfortunately 100% of OD will not be doing you any favours even if you hadn't gone over.
Sort that out, and wait a few months as Sparky suggests.