Seems to me your Victorian entrepreneur should not have hastily grabbed the first coach he found at reasonable cost from last weeks edition of
Pre-Loved Carriages, but instead done some homework whilst keeping his powder dry.
The layout of compartments and doors on that SDJR brake third does not lend itself easily to conversion - difficult to achieve a long saloon that is most desirable.
A big part of the trouble is the large luggage compartment in the guards area.
I’ve tried a few alterations but none are ideal - would help greatly if the servants could be accommodated in the brake area, then one side of the end compartment could be used for ablutions, the other door being a lobby entrance into the main saloon, but even then the door arrangement in main saloon is inefficient.
A typical late era saloon is shown here:
Bluebell Railway - SER Saloon carriage 172
Interesting to note the servants compartment was later done away with.
What other carriages might offer more flexibility in layout I wonder?
P.S. Can you confirm did he buy an old family saloon, or an old standard coach that he intends converting
into one?