Thanks for the replies guys.
Without the expensive mechanical methods, heat is pretty much the only way to shrink deep inboard on a fairly low crown panel. (on something more crowned you can actually knock a dent in and then work the dent out from the rear - working all the way around you can actually get more shrink than any stretch caused when puttting the dent in)
Torch shrinking is the old way, which is pretty quick, but not too controllable (not for me anyway).
The shrinking disc is really the way to go and that is what I have been doing - it is basically just a stainless disc spinning on a grinder - friction heats up the high spots which then shrink on cooling. It is very controllable, but slow. It is really also more of a metalfinishing tool than a shaping tool because of this. (BTW I spent some time with the guy who put the smooth disc on the map (and also the founder of Metalmeet.com), Wray Schelin earlier this year. He sells an excellent DVD on how to use the shrinking disc - search his name on Ebay if interested)
The problem I was having is that the shrinking process was very slow where I needed it to happen, and after all the previous shaping the metal is quite "upset". This often starts to cause all sorts of issues in other areas as the stresses and tension in the panel looks for somewhere to go. This condition can be helped by planishing or wheeling the entire panel (which of course causes some stretching again!!) As far as mild steel goes you can pretty much work it infinitely, as long as you do things to allow the metal too "relax" (apparently this realigns the slip planes at an atomic level

- there is a guy called Fay Butler who spends almost a day on his three day seminar teaching this and other theory............check out the Motorcycle Mania series - Jesse James thinks he is God

)
The thing is I think there will be more time involved "fixing" this panel than making another one from scratch. I'll have a go at the other side first and try to use a different approach with that one. I'll let you know how it goes.
BTW Zero (or anyone else) don't waste your time & money with the "shrinking hammer" - they simply don't work. Both the one like a meat tenderiser, and the one that twist and supposedly "gathers up the metal" do an excellent job of putting marks in your panel and not much more.
As to the cooling issue - how much air is needed? In stock configuration there is no ducting to the fan on the shroud right? I assume that whatever is sucked down from the vents is enough?
I was thinking if more air is needed than what will come in from below, I do have the option of using the heater tubes to bring air from the front (or even from under the back seat if noise isn't an issue - which it shouldn't be in a roadster

)
The engine compartment is a LOT bigger than stock, and I will be making up the plates to isolat upper and lower sections.
Just wondering if I should go to a lot of effort now, or fix it if & when it becomes an issue.
Chris - I will be retaining the back seat, or though I do plan to build a removable cover later.
Tony, does anyone actually drive their cars in the rain?????
Yeah if I went that route there would be all sorts of issues, and they would all result in rust trap areas too.....
I am not taking nearly enough pics, and the ones I am getting are all low res anyway.
Thanks
Barry