Well, rather than buying a top hat section for £14.50 + P&P I though that as it is such a smple profile I would have a bash myself. I popped into Wilco carmasters and 'lo behold' they do 4' x 2' sheets for £9.99 with a 1mm guage. Funny that as I thought that it was illegal to sell in imperial units any more.

I marked out the dimmensions as accurately as I could using a small punch rather than a scriber as that is all I had to the following measurements:
13mm
37mm
32mm
37mm
13mm
and left a 13mm tab on the left for the end tabs that attach to the inner sill. Now cutting this out with a hack saw in a brick garage when it is 24 deg + outside as I seem to have lost my jig saw was nice.
Now with my new vice and a hammer I vaguely remebered my metal work classes from school from20 years ago to form a pretty good similie of the original profile. The fact I was using a vice meant that I had to bend it out of shape to make the last couple of bends but it seemed to go back into shape okay leaving me this.

Lovely isnt it? Next I cut the offending length off and did a little prepping of the area drilled a couple of holes in the top of the repair pannel and plug welded it up. After 3 three attempts of pigeon poo I thought just one more go before I run up the garden screaming... and it worked.
I have now welded it in with 'mostly seam' welds and it looks the dogs danglys... if you can get excited about a bit of welding that is.
