DIPLOMAT 3201 keeps cutting out- repair or replace?

Hi- first post so be gentle!

we have a problem with our diplomat 3201- keeps cutting out, then as it cools it restarts itself. All power to the unit goes off when it does it, then five/ten mins later it comes back on.

It fused about six weeks ago, and when I replaced the fuse I noticed the light didnt come on any more- I assumed that the bulb blowing may have fused it. Now I am not sure that was the case.

With a bit more investigating I have noticed that when the oven is switched off and the fan stops rotating there is a metal on metal noise as the blades come to a halt.

I am wondering whether it is worth repairing it. From my limited understanding, it could be:
-the fan unit
-the element
-a safety thermal cut out switch
-something melted to do with the bulb housing
-(one or all of the above)

Might I be better off cutting my losses and just getting a new oven? Its a 2.125KW unit and plugs in at a standard mains socket. What I dont have is the dimensions of the unit- are they all the same like washing machines?

Many thanks

Matt