Nope, that bus is the last bus to Glasgow too.

If it's seriously delayed... Well, you're kind of SOL, as the trains don't even start until 9.50 the next morning, it being a Sunday.

The cab will not be cheap... I would suggest looking for an MPV and negotiating, but they know they've got you over a barrel. It's going to be in the region of £25 a head, though, you're talking 1am-on-a-Sunday rates.