and the answer is

Disk five, twenty minutes in.
I could have finished but the observer came into work at that point so I really had to stop.
Think I'll keep the last bit for the flight back up north, or at least the airport. It's going to be Bristol airport, so I'll need something to keep me occupied, that or the bar upstairs.

Which reminds me, had a rather good cup of coffee in Newquay the other day, and I realised that it IS possible to overdose on caffeine. And fun. It may have something to do with asking for a "large with an extra shot" without realising that a large already has three shots of espresso in it.
Buzz buzz buzz.