If the Wesley is C, C & Co, that explains the rarity of the transfer. The pottery closed c1832, the year that Adam Clarke died and North East potteries started mass-producing Wesley and Clarke commemoratives. So assuming C, C & Co made a Wesley and Clarke in 1832, they couldn't have been in production for more than a year or so. Of course, the Wesley could be older, and we don't have an Adam Clarke as yet.
Another reason I think that the Wesley is relatively early (C, C & Co era), is the quality of the transfer. As mentioned in my previous post, the lettering has long elegant serifs. It seems more likely that the 'Southwick' Wesley was copied from this transfer than vice versa, and that some of the refinement was lost in the process.
C, C & Co were pretty good at marking their wares, so if the attribution is correct, someone out there surely has a marked example.