After a bit of ECU soldering I think I have them sorted now though. I've not had a reoccurance since the last Galway run so now the air has turned cold and I've fitted a wideband O2 sensor, its time to retune my turbo's fuel and ignition maps

I've reset to the (v.rich + conservative timing) default map, tuned it so it would drive ok out of boost and played about with some of the in-boost fuel map (see below).
Original setup (GReddy manifold, turbo, 10psi and Saab 370cc injectors)
Running the tune for the old setup with the new hardware (so, way out) gave this result :
New base map default settings gave this smoother graph with a bit of wavering about near end, this was due to way too much fuel at the top end.
New base map run 2, lots of fuel pulled from the top end (its still v.rich), bit smoother, but torque still dropping way off and early, but happy with how the power is going

TBC'd