Some of the pressed glass attributions on the V&A website and on the Manchester Art Gallery website are known to be off (even of Manchester pieces) so unless there is source evidence it is difficult to be fully convinced.
Having said that, most of the plates in the PV 1881 catalog are generic, barring a few which they registered in 1873, and a couple that look distinctive enough that one hopes you could pin it to one glassworks, such as this one. Quite a few in the PV catalogue look close or identical to those in the earlier c1870 catalogue from Molineaux Webb. A couple of items look like they could be pre 1840 patterns, before PV opened in 1844.
If it turns out this one is a mould which was made several times over, then I guess we would have to ascribe the plate to Moore or PV and maybe others, if their catalogues had survived. As the moment though, PV is proved and Moore is inferred I would say.
It could also be argued the only plates PV had designed were the ones they registered, and all other moulds were bought in. Difficult to know.