So, I had a techie. The guys from the office were umming and ahhing about coming. I could do the show with just my friend, though the more, the merrier.
At lunchtime, I went to the arts centre and checked out the P.A. system they have there. It was well and truly up to the job, so I didn't need to worry about buying any more bits to make one. I paid the rest of the rental and suddenly realised that I had solved the basic technical problems for the Newcastle show. All problems left to solve would be the little on-the-day-style problems that would inevitably arise. The important bit was that it should, on paper at least, have worked.
After work, with a lighter heart, we did another rehearsal and the show dropped into our consciousnesses quite solidly. We felt confident about the run of four shows to come. There was nothing more to do but get on and perform the wee blighters.