[hcraig244]

This looks like an issue with the centre tapped transformer, I have read on the internet that a common neutral on the DC outputs of dual supplies of different voltages fed from centre tapped transformers are not allowed, this may be my problem.

When I disconnect the 24vac supply from the transformer to the 24vdc rectifier I get the expected 12vdc from the output of the 12vdc rectifier, so I know the 12vdc rectifier is working fine..I have no problems with the 24vdc side which is working fine, as this is the required higher supply im not surprised.  I cant see anything untoward except the common neutral to both rectifiers……..any advice regarding this would be welcome, as always ;¬)