Why not? they don't test the speedo on an MOT as far as I know... This was discussed on my build thread here, go down to Towed's lengthy answer
http://www.madabout-kitcars.com/foru...eedo#post42447
Now IVA that's another issue as it is checked. Anyway hope I'm rights as I've splashed my cash at Speedhut and have a GPS speedo on the way :-)