Thanks again Steve for the zener. Good use of a cigarette pack for shipping. 

New readings with only J1 connected are:

TP4 5.1V (with pot adjustment) now stable. Jaycar C106D1 (Alternative for S107Y1 SCR1 worked) + I did also replace the CR8 zener IN4734A (Jaycar)
TP5 8.9V. Which is apparently normal.
TP1 (Should be 60V) @ 80.2V 
TP2 (Should be 42V) @ 60.1V 

I was thinking of putting in a resistor on the 60/42V J3 outputs (for testing purpose) to create some load and then check TP1 & TP2 test points, but I've run out of time this week.

Am I now being over critical of these outputs, or have I missed something? I just don't wan't to blow the displays with these high readings.
PS. All cabinet bridge rectifiers and PS (60VAC) diodes were replaced and have a stable 60VAC input at J1.

you probably have a problem with one of the other zener diodes, transistors or capacitors in that part of the power supply.
TP1 should not be that high
the difference between TP1 and TP2 is within tolerance
you can try the following:
check that the resistors are still the correct value (R1 to R5)
replace C1 and C2
Replace Q1 TIP31C Transistor (sub for SW4F013)
Replace Q2 2N5550 Transistor