Job has to do with a reliable car going from point A to point B and won't break down. My husband has his own standards of what he thinks is acceptable and reliable. Personally I think you could find a decent car for under 8K, he whines that they're probably junk and having to fix them when they break down isn't worth the lower price. I think he's just worried about the car breaking down when he's having to go onsite for something, I think he's worrying somewhat excessively. Unfortunately his boss is gone this week and we're supposed to be going on holiday to visit DH's family... all this is pretty bad timing. Don't know how that's going to work out. 
Sounds like the issue is with your husband, not the bank. I'd put my foot down tbh, to spend £8K on a car when you only have £12K saved up is madness to me. I don't really buy the reliability factor, he can get a good quality reliable hatchback, like a Polo for half that £8K and he can always get AA cover or whatever to come help him out if he breaks down.
Tough one really as I don't really see where he's coming from, if a car is that important than work should supply one, the fact that they're not gives him carte blanche to drive whatever he wants to drive. Cars aren't as much of a status symbol here really, many people drive odd or vintage or quirky cars, people tend to go for economy (because fuel is so blooming expensive!) rather than having the larger sedans etc.
No one will give him a second look if he drives a little hatchback *shrug*