I'm new here but did get some data on the Martin Baker MB5, which I believe was the last development they made before concentrating on ejection seat manufacture.
The MB 5 was the contra-rotating prop desisign, which by all accounts was superior to most British Fighter designs of the day, however, production was geared up to current designs and it was never put into RAF use.
I have a booklet called 'Mr Martin's Memorable MB5', which gives a detailed history of MB design up to and including the MB5. It also has photpgraphs and a Flight Magazine type 'cut-away' sectional view of the MB5, plus several side profiles. I also have an A3 sized detail drawing of the MB5 (top, side, lower views) with sectional profiles and marking/construction detail.
All of these were supplied after contacting the Martin Baker company, who put me in touch with thier modelling clud representative (I have his details also).
If you want any of this, drop me an E-mail and I'll copy it all off to you,