Thanks everyone... I've been quoted £60 for the sill problems and £30 for the cab floor.
Well, that won't sort the jacking point problem out, because it goes MUCH deeper, and is a difficult job IMO. If you picked it apart and cut all the rusted metal away, there would be nothing anywhere around it, just the heavy jacking bracket.
A £60 repair in that area would mean:
a) it'd continue to rust immediately thereafter
b) very unlikely you could jack the van reliably
Difficult to put a price on it, to be honest, because a 'really' proper repair there requires cutting and bendingthe jacking points well back, cutting lower sill plate, outer sill section and internal vertical stiffeners right back, and replacing either from custom fabbed metal (of decent thickness) or from new sill panels. Stick a screwdriver straight up through the round hole in jacking bracket and it'll no doubt go straight through, and if after driving in wet, water will maybe come out...
Try to get whoever fixes it to make a hole in that lower sill area right under jacking frame, to be plugged but will allow it to be drained and dried occasionally. Make sure the internals are treated immediately after weld repairs with something like Dinitrol
£200 /jacking point would be 'cheap' I'd say, as a guide, but then ££ doesn't guarantee anything, the time and experience and care does though, and these days that tends to mean Yours Truly, or a keen and good amateur.
If it's to be a long term ownership, you should know that many welded repairs are likely to start rusting again much faster than before unless great care is taken.. because the sections cannot easily be put together inside out, like they were in production.
I'll stick some pictures up of the sort fop thing you might be looking at when it's all cut back to good metal
The floor and steps are not such a problem, also look under the seat (above the front suspension spring/damper unit)