Well I got it out, only JLR could have thought of putting a thin steel insert inside the plastic so the screw corrodes inside. The plastic would have been sufficient IMO. Hope it shows in the photo.the remains of the screw is there in all its glory.
Not yet i am plucking up the courage to put it on the drive and re seal the pump institu and tap it towards the engine to get the modulation back, its just i bit cold out there atm when theres a nice warm house to sit in