Thanks for the effort. I located a cheap copy of Fairbairn's and so have it on order, should be here by next Wednesday, so I can convince myself in the future. In the meantime, I noticed some Eley and Fearn spoons at auction on Fleabay sporting the crest below:
Different base, crown versus vine, but the paw is very similar, which indicates to me some sort of common source and not just a one-off design. Will keep an eye out.