OK, I'm back on the job.
Now that all of the cutting and drilling has been done, it's just a matter of welding the uprights to the lower rails.
Do this on a flat bench and clamp both pieces to the bench to prevent heat warping the tubes. Make sure the yokes face the right way (to the rear) and the axle holes are in the right position.
When the upright is welded, fit the gusset as shown below and weld in place.
Repeat for the other side.
Set up both welded assemblies on a bench and clamp in place so that the distance from centre to centre or the yokes is 295mm. Check that all is square and that the distance at the rear is 295mm centre to centre.
The back cross bar can be placed equidistant from each edge and welded. Then the second cross bar can be done in the same way.
Clean up all welds and surfaces, hit with some paint, put plastic end caps in the back of the rails and cross bars, fit wheels and axles and you're ready to go.
Please ensure somebody assists you if you are unfamiliar with lifting the bike!
I've included JPG shots of all drawings as the first lot are not too clear.
If anybody wants my amateurish Google Sketchup files just ping me a PM.
Main drawing below.
The others, hope they are a bit clearer.