I've given up with scepticism and opted to believe the first story I read on the internet for everything.
But yes, in my day, the £5 note from a favoured ATM was the standard denomination of drinking token. I remember the super-strong beer served in the Augustus John on the Liverpool Uni campus was a princely, if awkward, £1.05 a pint – though if you got past four of them in an afternoon you'd probably wake up in Bootle at 8 pm to an irate bus driver. The 80p you had left was enough to get you back to Tuebrook though you'd need another ATM visit for the kebab purchase.
You could save money by undertaking in a foul pastime known as Addlestone's cider, which was 90p a pint but honestly, you'd always spew eventually, quite often through your nose.