I've put the MPG calculator data in for the last week or so.
Its not quite as accurate as it was, as the speedo cable broke with an unknown amount of fuel in the tank, and I can't remember how much was in when I fitted a new cable either.
I'm not sure my speedo isn't under-reading quite a bit - I find an indicated 70 makes me one of the faster vehicles on the motorway, and if I do 50 in a 50mph zone I find I rapidly catch up people apparently doing 40mph.
I suppose I should find someone with GPS, and borrow it for a few minutes, for the definative answer... if the same error is present in the oddometer, that would massively improve my MPG as well, probably putting it nearer the 30mpg or so I would expect from a 200.
By the way - a new part not to buy from Britpart - Speedo cables. The one that "broke" hadn't actually broken. The end was so badly crimped together where it took the drive from the gearbox, it was just not going round. Replacement is Bearmach - it looks much better quality, the driven end was even a proper bit of metal bar, rather than badly crimped cable. It might just last a few miles longer than the previous couple of Britpart cables then.
As I type
11 years ago