Reached 100% with 8 days to go
Well, we got there, with plenty of time to go, thanks everyone!
Will see how it goes, but with eight days to go, it might well go over the target. Currently trending to £740 (or about £670 after the kickstarter and payment processing commissions).
If so, as you'll see in the project description, stretch goal is to get a discounted new computer - instead of a second hand or refurbished one - often new computers cost hardly much more than the second hand ones, especially after you add in cost of a one year guarantee. For instance, last summer's 11" screen Macbook air is selling at a huge discount now, under £600, on amazon, and it's a pretty decent machine by user reviews and specs, if still available by end of project - Specs here.
It's a small screen of course, similar to a tablet - but that's no problem for debugging with an external monitor.
That's icing on the cake though. The main thing is to have something that can run the latest Mac OSX, and reasonable hardware guarantee of a year or so, and that's going to happen :). .One way or another, it's going to happen now.
Thanks again everyone.