...however (massive) thanks to Huskyracer for letting me get my hands on a tight B14 at very short notice (and also huge thanks to Andy for delivering it)...a few days later, Nessy had had a heart transplant, and was a different car.
Today, a year (and over 15k miles) since the project started, Nessy passed its MOT requiring just a small patch of welding to the rear box section (at the infamous point where it joins the cross-piece). It currently stands at a gnat's cock short of 198,000 miles.
In the last year it has needed the following...
Engine (ho ho...)
Radiator
Misc hoses
Rear gearbox mounts
Ignoring the cost of welding it up to begin with (I could have bought a clean one for far less), parts cost for maintainance has been under £100, including two oil/filters/plugs services. I've also yet to drive it more than a couple of miles when it has done less than 40mpg.
So...in conclusion...I took the most knackered 340 going, spent peanuts on the oily bits, and it has been a faithful, economical, and damn pimp-looking servant. Nessy, we salute you!

cheers
James