Mad jock - it’s not perfect but it’s the best thing out there by a long way, and whilst BA would prefer you to seek security from elsewhere they will ultimately stand behind your loan. Yes, the rate may be higher but they’ll do it (even if reluctantly), which is a damn sight more than any other airline, some of which want paying for an overpriced TR upfront.
To put it in context, there are guys that trained a decade ago did FI, TP work and only now applying for BA DEP, and you will join BA from the word go –saving you ten years and a huge amount of stress.