"N_Cook" writes:

All seems original in there and o/p devices TO3 Motorola, badged SCSP1
and SCSN1. Presumably , as only +/-24V rails 3055/2955 would be
adequate

This schematic shows MJ3001 and MJ2501 as equivalents for SCSN1 and SCSP1:
http://www.drtube.com/schematics/marshall/2099u.gif

These are Darlington pairs, so they have much greater hFE than the
2N3055/MJ2955. They're only about a fiver a pair from Farnell.

--
Adam Sampson http://offog.org/