Fuse 25 keeps blowing - why?

[Zippee]

I have a problem with fuse 25 in my T350, this looks after the speedo, elec mirrors and LEDs around the light and fan switches.
I'm a total numpty when it comes to electronics so any ideas what could be doing this? I'm assuming since the light/fan LEDs and mirror switch are low load and also not in use when it blows that it's possibly going to be the speed sender - but why? Bad earth?
Also, when it last blew I removed the old fuse and put a new one in which left all the dash ablaze, removed it and the speedo worked in a very spazzy fashion. Stopped the car a mile after, re-input and now all is fine again - until the next time it blows I guess.

[fredd1e]

Sounds like you need to take it to someone who knows what they're doing.. HTH.

[Zippee]

Shes going in for a service on 25th June, unfortunately I can't get her in before that date. May have to try a local auto electrician but I'd ideally like some hints as to what could be causing this, especially as most auto elecs won't have experience working on TVRs electrics.

[Targarama]

I'd guess it may be an earthing problem from the second part of the problem you describe. Check all the earths are nice and tightly nipped up.