hi Ross - sorry, can't help, but just to say that I can see what the guys here are implying when they comment about the colour. Your bowl appears to lack the bright 'golden amber' shade of W/Fs, and to some extent the same appearance applied to pieces from both Stuart and Webb -although there is more of a possible similarity in a few of the Webb pieces - but as you say they appear not to have produced trailed pieces. Appreciate your comments though regarding this being of similar design to W/Fs. with trailing.
Your bowl looks to lean more toward a dusky dark pinky/brown, perhaps more typical of Continental production? - there are others here who will know far better than me re your comments about Walsh - but again my uneducated guess is that it doesn't match any of their colours.
As to Richardson - no idea even if there are any catalogues available showing their designs - certainly don't recall anyone referring to them here.
Very nice piece though - unfortunately, I think it's going to be the lack of backstamp that's going to be the stumbling block here. Let's see what others think.