Years ago I picked up a load of Airfix Mk2D coaches on the cheap.
Being cheap, most of them were Brake Second Opens, and most of the rest were First Opens.
Many of them were also in poor condition. One turned out to have broken/missing bogies and gangways. There's a distinct lack of stepboards, buffers, and so on.
There are also shortcomings in the original Airfix representation -- such as the FO having 2+2 seating, but at the correct 7-bay pitch. It should be 2+1 for a proper FO...
This makes them ideal conversion material.
This one is my first attempt. It's an early Mk2E TSO, created from the non-brake end of two BSOs. The exterior, the glazing, and the interior have all received the cut'n'shut treatment, creating a proper 8-bay 2+2 seating layout. The roof and the bodysides have been cut at two different locations.
Glazing is only in temporarily installed -- it'll need to come out again when this finds it's way to a paint shop.
This is my second attempt. It's a Mk2D FK.
It's interior has been created by cutting and shutting two Hornby Mk2 BFK interiors. The paint isn't great on this example, so I may elect to repaint it too. It'll certainly need a new number.
Two further coaches are on the workbench. I have an FO shell in a particularly poor state of disrepair, which has been put down next to one of the brake ends of the BSO. This should be the correct pieces to make a BFK, although I've lost the cut diagram I used to have bookmarked many years ago.
I also have two spare FO interiors, and I'm cutting out and repositioning individual seats. If I can separate enough to form an airline section in the centre, it should make a convincing 58 seat Ex-FO declassified TSO.