Following up on my previous request for some help, I've been doing a lot more digging around and have come to one conclusion. We don't have any small engineering shops left ....
I found a local engineering firm who could do some of the sheet metal work I needed finishing and who could "get it done by Wednesday" - I should have confirmed which Wednesday :( They are doing me a favour fitting the job in, but the rather large some of money agreed did assume that I'd have the boxes back to assemble by the end of the week.
None of the 'directories' on the Internet are of any use for establishing who does what so I'm wondering if it's worth putting something together? Something that we can search through for the sorts of jobs that we can't do easily at home, and which we can rate suppliers when we find them performing well. While the bad performers should probably be commented on, my personal thought is that only services with positive feedback are displayed.
The amount of time I've spent trying to lay of some of these jobs, I should just have got stuck in - sorted out the right tools - and got on with them ;) In the end I'd be able to simply do the jobs again next time.