Speedo not working

[gf15]

Hi,
Used the TVR (V plate) for the first time in a couple of weeks and the speedo & analogue trip meter do not work, they were fine last time. I have read the relevant section in the bible and the fuse is OK. Looks like either the sensor or the speedo connection / part. is it difficult to get to either?
what is the most likely ?
Any input would be much appreciated.

[shpub]

The Bible 2ed has a big section on this. Access to the speedo means taking the dash off. The sensor is under the rear axle. Testing this things is well nigh impossible unless you have an oscilloscope to look at the waveform . Cleaning the sensor and making sure the sensor gap is as small as possible without touching might be worth a try.

[chim_boy]

I had the same problem yet today my speedo suddenly started working again...

Could it be anything to do with water ingress in the ECU?