Slight update - ECU is FINALLY on its way back from California (It was DOA), and I have managed to get some time to finish welding up the manifold.
I decided to go buck mad and get a 60mm wastegate. This required quite a bit of awkward butchering to the manifold I had bought. The manifold I had originally bought was for a different type of turbo to mine (It was for a T04 flange and I have a T3/4 GT3582) so I had to weld an adapter plate on to it (Yellow arrow) - the turbo was then hitting the manifold - so I had to get a stainless spacer milled for it (the only bit I havent done myself!) indicated by the blue arrow.
The red arrows in the diagram below show the bit I had to physically make in order to make the 60mm wastegate fit - it was originally designed for a 40 something mm wastegate which I decided would be too small (You can see it the way it used to be in the previous threads). You would not believe how long it took to get the angles right on that damn thing. More than one time I was for throwing the lot in the skip and forgetting about it..
Few more views of the handywork - not too shabby if I do say so myself!
A shot of the huge ass wastegate
And finally, a couple of shots of the angle I need to weld the wastegate on at
