Thanks Peter for your information. It was the transformer
and the 7K resistor is fine.
Here is an update:
I disconnected the transformer from the rectifier and connected up a 140 volt AC output transformer to the bridge and the DC was at 163 volts on (C) and the HT on (D) was 114 volts and all was ok. I also tried a new rectifier and still got 114 volts DC output.
It seems that the secondary of the transformer has gone faulty and producing only 45 volts, so has anyone got a transformer going spare? I think it needs to be (240 AC in) (200V out at 150 mA) and (6.3V - 0-6.3V 0.6 mA).
Here are some more pictures out of the detector of my AR-88D, the generator was set to 10MHz AM and there was a good audio output.
Thanks again,
Gezza