Green’s Dictionary of Slang

bang up against adv.

also bung up against
[bang adv. (1) + SE up against]

very close to.

[Aus]Bulletin (Sydney) 31 Oct. 13/4: This was the lot on which McCracken’s brewery was built bang up agin the church. Somehow beer has always been fairly close to the church.
[Ire]Joyce Dubliners 260: Drive bang up against Trinity College gates.