BBVA essentially just offer secured loan like many other high street banks do, with a few nice perks e.g. up to 24 months payment holiday so you don't make payments while training and then up to a further 24 months reduced payments.
The highest unsecured loan I have seen is £50k with First Direct but I don't know how feasible actually getting that loan may actually be lol especially for flight training!
As the other replies have suggested, modular seems to be the only option unless you have the security.
For me it's a self funded PPL, then I'll build up time going flying trips and enjoying flying. After that I will consider taking the biggest unsecured loan out there to do the ATPL ground school, then a CPLMEIR course, some good options going for about £20k.
Thing is, depending on income that could all take a while, it also doesn't account for any extra hours needed/living costs/MCC/JOC/type rating etc etc etc.
Good luck with whatever you end up doing.