Hi there
I'm currently trying get the funds to complete my fATPL from HSBC as they seem to be the most clued up of the major banks when it comes to aviation. Their literature claims their professional stidies loan can be used to cover the cost of an entire course and payment only commence 6 months after all training is completed - interest is HSBC Base Rate +2%.
If successful in my application I will post on here. Im after about £20K as I have already done a PPL and have 200 hours. Like you I'm not in a position where I have a great credit rating due to a few problems a small business of mine had a few years back.
Good luck
PS I thought CDLs only had a limit of £8K - hardly enough to get you through an ATPL?