Matador Mk1A

Hello,

I am trying to restore a Ransomes Matador Mk1A and have a number of issues, but this one could be a show stopper.

I've made a start in establishing what's good and what's not. Started in a relatively sensible order, quick wipe with oily rag, empty fuel system dust, found Amal carb service kit & fitted, also found fuel tap & bowl service kit & serviced etc. Clean fuel achieved. Have a spark, albeit seemingly varied in strength, but it's on it's original plug, fresh plug ordered. 

Thinking about starting so before that I've had the gear side inspection cover off to find a piece of steel bent around the Cylinder sprocket perfectly shaped between the chain and sprocket. I believe it's the chain tensioner been ripped off and dragged around. I've seen a few manuals for mk2 and newer, these seem to have a sprung arm rather than what mine seems to have had which is more of a guide. Many older motorbikes have this arrangement, so ok, but, where am I going to get one of those from? I can't even get information about a Mk1a, a general search is turning up nothing so far. Any suggestions?

Chain off now by the way, so no danger of damage if I fired it up.

Could perhaps cobble something together if I can't identify the part. A drawing of the original kit would be a nice start.

Any help would be very much appreciated.