The cabinet is not being touched !!!!Some useful contributions.
Not SETs obviously - they would run too hot - so push pull; and not American as they like to hide their valves.
Maybe a World Audio Design? The Art Audio was a good shout from Brook.
The wood facia requirement is a problem, but you could sit the selected amp on a lovely maple, or similar, wood platform. That would help isolate it from that big cabinet.
If I remember correctly the cabinet has doors. What about converting the RH door where the Vincent is, with a part or whole perspex replacement so the 'glowing bottles' are clearly visible? (You could cleverly leave a few discreet gaps in the design for cooling purposes.)
Jack NSM
When we designed the unit the doors have a 4.5 mm gap along the top which you can’t see because of the overhang .. when we tested with the Vincent hybrid there was enough gap to keep the inside at a constant 60’C with the door shut