obviously its years after the question, but for the record, in case someone else has use, I did replace with the pump, from team f5r in Poland.
solved my fuel problems immediately.
I had previously bought two pumps, at considerable cost, and even bought those membranes from Turkey and oepned up a pump to replace them (lasted approx 2 days, do not recommend at all....) so the Bosch pump seems to be a worthwhile purchase.
Would be good to knwo if that eliminates any issues with E10 fuel too!! We know the pump membranes were damaged by E10, but are there any other components at risk?
Now some years later the engine is doing similar stuff, injectors reporting low pressure, but it could be the pressure regulator (also got one from F5r) or sensor, or even a fuel line issue.
Given how the pump works I doubt it is a probelm, but I've had no idea where to take a pump for high pressure testing.
even after all these years I'd love my Signum back on the road, and one of these days I'll get back to lookign at it.