Thanks PhilMH, I'm not sure if the orange/white labels are from 1974 though.
Catalogue number fits in between the other 1975 releases (but sometimes there is no logic in release year and catalogue number with Trojan).
The blue label must be a repress, because Discogs has a white/orange label version which shows 1974 on the labels, as well as another white/orange showing 1975. I don't think the blue would be any later than 1975, because Trojan Records Limited and B & C Records Limited were liquidated that year, and the catalogues acquired by Marcel Rodd's Saga Records company and resurrected as Trojan Recordings Limited and B & C Recordings Limited (and if there's a version of this album with those company names, Discogs doesn't have it). Anyway, as it appears that this catalogue number was first used in 1974, that should be the year used on this entry.