Well 48hrs later, and car still has build up of static. Which is weird considering the battery was disconnected.
But the good news is that I found our the problem with the gauges. It turns out that the connection into the speedo cluster can become worn. I removed it, looked at it , and then put it back. Now it is all working, even temp gauge is playing ball.
So booking mot tomorrow, and hopefully be back on the road soon.