As it is now common knowledge that my Serbo-Croat is not up to scratch I am now taking night classes in Klingon. 

Thanks Nicko there is a small dia hole that passes through the top of the channel with a securing tethered eye plate at the side that had the remains of a piece of string on it – so likely a roller/pin at the top.

Much Appreciated

My conclusion is that the normal seat is a radio operator NF10 seat made at Broughton and the seat with the extension is a pilot seat from a T11 made at Christchurch.

Brian

Lincoln bombardier seat now fully restored.

Stripped back to components and then to bare metal before re-rivetted problem  parts before reassembled, repainted and then a matt acrylic top coat to protect the paint. Handbrake seat lever has been freed and is working well.

New green leather cushions.

The base was on a thin aluminium sandwich with a plywood middle – that had the 35  of 80 written on it that makes me wonder if this was one of the Metropolitan Vickers made Lincolns.  This would fit with the non R3  inspectors stamps. The part numbers fit with those on the Lancaster pilots seat that have the same parts

The top sheet aluminium of the base was corroded >> 50% so we have  moved the bottom layer with original paint to the top and replaced the wood.

The map case is a resin/paper item with a canvas strap.

A nice project. 

My neighbor is a 90+ year old RAF pilot who flew Lancasters over the Arabian peninsula post war and was very appreciative of the memory of sitting in the seat.