Ransomes marquis spare parts, carb and exhaust

Exhaust - Think that you can still get the genuine article from either Meetens or Villiers Parts.

Assume that the screw that you need is the throttle slide stop screw that sets the idle position when the slide is closed. Again, Meetens or Villiers Parts. It has a nut on it to lock the setting. I think that it is basically a standard BA sized screw  so if neither of the above can help it shouldn't be too much of a problem.

Thank you, yes it's just below where the needle fits into the tube (below throttle cable) to the left hand side.