Linn Axis psu almost fixed (i think!)

[martiny]

I have a Linn Axis PSU give up the ghost but I am determined to fix it one way or the other.
My problem so far:-
Load resistors R2 and R3, and D1 burn out so they are replaced.
I am now getting 320v on HT line, however I am only getting 6.3v out of regulator instead of 13.5v.
I have replaced Q1, Q2, C3, C4, C5, R4 and R5 but still getting same o/p.
I have 0.6v across tops of C4 and C5 which I think is correct but only 7v across R5 which I dont understand as these resistors measure correct so should act as potential divider across 15v and seeing as they are 15k and 180k respectfully should have approx 14v at base of Q1.
The good part is that the motor seems to turn if persuaded and it does speed up when button is pressed.
Any ideas would be gratefully received,
martin