Hi Chris
If you don't feel confident in building the speedo tester, its not too difficult to remove the speedo and send it off for testing. This is what the dealer would probably do anyway.
There is a large plastic threaded retaining ring around the back of the instrument case which you simply unscrew to allow the instrument to be pulled forward from the panel. There is just enough cable to give access to the 8 pin plug at the back and remove it. Then the two bulb holders clip out of the case and the instrument is out.
I don't have first hand experience, but other people on TM have sent theirs to a company called speedy cables for bench testing.
Regards Tony
