Hi Andy and All.
Your approach to big amp design using a bridge cct is interesting but the
concept is old hat. Like you say it is based on the decca design except for
the supply voltage which you derive directly from the mains 230 v supply.
The rectified 230v and capaciator smoothing could be dangerous but no more
dangerous  for us that have built hf amplifiers using tubes with 3 to 4 kv
on the anodes at currents in access of 1 amp. I agree not for those with
hand wobble or sticky fingers.
However since you are at the launching stage with such an amplifier and have
worked out some of the critical component values  and impedences I though
you might like to
give others the benefit of your knowledge. IT AVOIDS RE INVENTING THE WHEEL
I would like to hear your signal using this amplifier and dont forget to
WATER COOL THE LOADING COIL.
Put a disclaimer on any cct diagrams that you produce that you will not be
responsible for any EARLY EXPIRY of those building and using such an
amplifier!!!!!!!!!!
73 de G3KEV