Hi Jon
I have seen the Daniel Cooper's Garland at BL 11621. b. 11. 5.2 and the Molecatcher is actually not there in the garland unfortunately otherwise I'd have copied it. The garland is in a small volume with 'Songs' on the spine. It was 'Bought of Kerslake, Bristol for £1 16s then in 2 volumes', and bound into one in 1847. There are 22 garlands in the volume all printed by one or other of the group you mention. Some of the songs are datable so a rough date should be possible. I'll get on it. I remember looking at this set of printers about 6 months ago and I don't remember them being that early, more towards 1820 but my memory might be inaccurate.