cheers for the replies guys, ill have a go with a new set of clocks but im not sure it'll work as when i spin the cable like you say the speedo moves.

i've had the clocks out and driven the car with them removed as so i can see if the actual cable is spinning but it doesn't, occasionally spins for a few seconds but then it stops again.

whats the best bet, gearbox rebuild or just get a new rst box. not sure i want to loose the lsd and get a 3i box?

thanks!