Just been on a few other web sites, found one that has cured the problem.
And it was easy and saved me £££££'s
Un-plug the dryer, on the back of the dryer you will see an oval cover with about 6 screws on it and a little cover with 2 screws in it.
Take out the screws and remove the covers, in the larger cover you will see the heating elements that produce the heat for the dryer, and you can see two electrical sensors above them, the possible reason your dryer keeps tripping out is that they have got water in them, you will need to dry them out either by leaving them to dry or like i did got the misses hair dryer on them.
Re-screwed it all back together and it's now back up and running.
This was all caused by not cleaning the big condensing filter at the bottom of the dryer on a regular basis, this then builds up moisture inside the dryer and on those little sensors.
Hope this helps!!!.
Scott, January 2009