Thanks for the feedback lads.

I've removed the fuse box and discovered the remnants of old fuses in the bottom. I replaced the fuse but no good. What I did notice happening is this.

Key out of the ingition. I fitted a new fuse - the doors were shut and the fuse didn't blow. Open either of the front doors and the fuse blows. I don't know if the interior light is a factor in this. The fuses blew with the light in the on and off position.The rear window is still down. I guess tomorrow I'll grab 10 or 20 fuses and attempt some kind of process of elimination.