Ok, stil having coolant pressure issues. So far the following have been done:
New expansion tank & cap
Heater matrix blown through and clear
Header tank checked for hydro-carbons......all clear
Compression check on all 4 cylinders, all fine
The engine has been changed (its had this issue since I got the car, it now has the LEH in and it continues.
Only remaing thought is the small secondary coolant pump maybe seized etc. anyone any thoughts, slowly runnig out of ideas.