Thanks for all the kind words guys.....
I would assume that most of the units that are on the market are pretty much all made the same way. The cooling unit is a self contained insulated 'box' that has either a wood (as was my case) or metal casing around it. Simply remove the casing (look to the back for support bracket and remove them, then slide to insulated 'box' out) and use the outer casing as a template for the new one.
Wonder if I could market these and make some $$$ hmmmmm
Cheers
Mark