ULU and Birkbeck bars - non UL students?

I've previously been into the Birkbeck bar with a University of London student (not Birkbeck). I expected to have to sign in as their guest, but I was allowed in on showing my university card (which is a non-London university). From what I understand, their policy is to allow any NUS affiliated student into the bar. Is this correct?

I was also wondering if anyone knows anything about the ULU bar? Do they allow non-University of London students into their bar without a University of London student?