Going back 7-8 years so, maybe longer, I bolted a short route out right. Grade 20/21 sounds about right. It think it had three bolts, wedge expansion with hangers. Not glue-ins as in most of Strubens. Also the chains were of the type used by the MCSA at the time, with the chain split and rewelded around the Hanger. These chains were then plated and had a yellowish colour. If I remember the two chains were of different lengths, thus the bolts were slightly staggered. This route was also near the left side of a small outcrop.
It has been ages since I was last there, and my memory is not that great, but the picture you posed looks familiar. Not sure though.
I really do not want to claim someone elses route, but if the above sound right then I called it "Looking for Snakes". We happened to stumble across a small snake at the base of the route and tried in vain to find it afterwards in the grass. Just a bit of useless info for the snake lovers outthere
I will try and pop past there sometime and then confirm on this thread.
Andreas