Hi B00!!!
We were at the Lowry at Xmas!! I don't know about paying in cash but I don't see why they wouldn't. There are some desks there on the right when you go through the doors where you can get tickets so I would assume you can pay by cash.
I just wanted to say I was there at Xmas! Saw Chesney Hawkes in Dick Whittington, blooming brilliant and yes he did play 'that' song! ;o)
The tickets were a gift so don't know about paying for them as someone won them in a raffle (donated by Chesney himself) but lived too far away so we got them :o)
What you trying to prebook? Is it Wizard of oz?. We stayed at the travel lodge on the Quays and enjoyed it so much I want to go again this year but stay longer (if we can afford it!)
Sorry for waffling, bet you thought you'd got a useful answer when you saw you'd got a reply!