I want to thank all of you for your help. Every time I come here I always find people willing to share some knowledge with us ignorant folk.
No, no, thank you for posing the question.
I find it fascinating to try and solve the enigmas......
Machins were not meant to be easy.
So here are our contenders, forget Scott and his colours. we may have a problem there.
Stanley Gibbons. 35p contenders. (ALL eliptical [syncopated] perforations)
35p photo enschede YELLOW 2 bands Y1692 sheets
35p photo harrison YELLOW phophor paper Y1693 vertical coils
35p litho. Walsall or Questa YELLOW 2 bands Y1755 booklets walsall..nat trust booklet questa
35p photo de la rue SEPIA 2 bands Y1694 sheets
35p photo enschede or de la rue YELLOW OLIVE 1 centre band Y1695 sheets , brunel booklet DX36
No mention of green
So, If you have correctly identified the first stamp as litho.
it must be Y1755 35p. yellow 2 bands 1st November 1993
By elimination, your second stamp (right hand side) must be Y1694 35p SEPIA 2 bands 1st April 2004 (REDRAWN)
or.........Scott MH352 suggested as "Olive Green"...prove it by guaging the top perf at 14.75........
I hope that solves that.