i've had it now. the car is clearly a rouge and determined not to be fixed....
just spent 2 hours at the garage...
run out test on hubs = fine
VT test on the discs = fine
pistons in calipers = fine
new braided hoses on front = obviously fine
fluid flow from master cylinder to and from. not tested, but pistons in calipers were pushed back to remove an preasure, and still had problems on way home. so its deabting the fact if there is a return issue with the fluid... potentially showing problems with blocked pipes or valves..
so. do i either spend a grand or so completely replacing the whole braking system and front end (hubs, shafts, gear box, bearing and anything else that spins), or buy another and risk other problems and transfer my trick bits over.