That's a very good looking trailer, Gareth! I will come back later to ask you about "painting" it and such.

Thank you for all the advice about welding and brazing. I reckon I'm going to stick to my stick, though, and continue arc welding it. I've got a lot better already and my later joints seem much improved. I'll get some pics up soon.
I just need to get something built ASAP, really.

In general: I have almost finished the basket of the trailer. All last week it kept raining five or six times a day, so I never got my welding gear set up to finish it off. Hopefully I will do that today.

Then I need some wheels, which I think I can source quite easily. I may also need some more tubing, since I need to construct the "wrap" around the outside of the wheels, to hold the outer drop-out. I think I'll use dropouts cut from actual bike forks, to save fabricating those from plate metal.

Oh, and regarding the longtail bike - the mountainbike frame I was going to use is actually aluminium, so I will need to find another one (I want to weld it). There don't seem to be many suitable bikes for sale around here at the moment.