Hi Doug,
Our thoughts were to do a full restoration of the van - paint/ engine swap (modern)/ gearbox/ interior and so on. However, not being mechanically minded and useless with my hands (actually, I do mean that literally due to a few nerve impingements!) it soon adds up. Thankfully we have made good friends from this forum who can do the work! Engine wise, it is standard as is. I would suggest that it be looked over for your own piece of mind as it hasn't moved much in a few years. The top hose could do with replacing (will ring Martin tomorrow to order one). After considering a modern swap, of which there are only a few we thought we would be best to rebuild what is there (it does still sound like a sowing machine, very nice). I saw a post recently suggesting a rebuild is around £1000. You would want to add a few go faster bits, SU carb, a ported manifold etc, electronic ignition and so on but it is not mega money. Finding an overdrive gearbox may be difficult but Tim is offering a six speed conversion using a Lexus gearbox which are very solid and very cheap - £150/£200 range for the box.
Simply put, for a full restoration as standard you are looking at £16-£20k unless anyone can suggest otherwise? Many have spent more, many have spent a lot less if they can do the work. We were quite specific with what we wanted so it would be between that range. One chap quoted us £8k just for the paint job and I know another guy who has been quoted double that - just for paint!! It all depends on the depth you want to go with it.
Ultimately, you could have a chap look over the engine, change the top hose and away you go. My van before was an auto so this is the first manual I have had and I would say that changing gear is novel, I would look to change the bushes to tighten the gear changes but again that is very inexpensive. As it is you would be getting 45mph or there abouts, but alot more is possible with a few common sense changes.
It may be worth speaking to Martin Maltas - commervanspares.co.uk for details for more specific renovation costs, especially if its for a specific requirement such as just the engine work etc.
I need to send you my address which I will do shortly!
Will look forward to seeing you both.