Hi GE115b,
easyJet were underwriters for my type rating costs. Once you've got the confirmation email from easyJet about what amount of the loan they'll underwrite for you (as there are a few different offers for the MPL scheme I believe) then BBVA will get in touch and you get the loan through them.
I think in the application you send to them you have to send a credit report from Experian and then maybe they use that somehow to determine affordability. Not exactly sure on the finer details to be honest. But your parents/friends/family credit doesn't come into it if easyJet are underwriting it.
Hope that helps a bit. Maybe others can shed more light.