background check

I have a friend who's at Uni in the UK. He's been busted for drinking and driving. The question is, do banks in the UK check for criminal records and is he fscked?
And if so, what are his other alternatives? Banking in other countries? Im not familliar with UK law.. is it possible to have the record erased?

He's feeling pretty bad at the moment and I really want to help the guy out (eventho im pissed off he did something soo stupid)

appriciate any input

If I wrote double major finance and accounting on my resume when I interviewed, and later dropped finance after receiving the offer, would this look bad or would a company not care?

Also, when they call my previous employers, do they just confirm the time periods when I worked or do they ask them about my performance? I'm not on really good terms with one of my past employers.

I listed only my junior year GPA on my resume - it is 0.4 higher than my cumulative GPA which I didn't list. After getting a full time offer at a bank, can I get dinged if they don't like what my cumulative GPA is?? I would appreciate honest and not judgmental feedback. Thank you.