Yes Rob, the limber came from the same museum I visited. The owner of the salvage yard used to have the scrap contract for the base back in the 60s through to around the early 90s. Sometime in the 70s, an officer at the museum wanted the "junk pile" cleaned up. There was a nice little pile of pieces that came out of that mess including this limber, the remains of 17 pdr, some 25 pdr bits, an honest John rocket launcher, a 6 pdr carriage, a couple of German guns, etc. I think Clive at the museum mentioned they had two of the guns and only one limber, so it appears I likely have the other one.
When I found the German 20mm receiver buried under the carriage, I asked Al why he would have put it there. He said it was likely because he was just dumping the stuff off so he could run out for another load.