BJH had a loyal following, but never really set the charts alight. But they were gaining a big fan base in Europe, especially Germany and France, and so a move to the Polydor record label seemed obvious.
This brought a whole series of albums, including Everyone Is Everybody Else (1974), often regarded as one of their best and including For No One, Time Honoured Ghosts (1975), the fantastic Octoberon (1976) and more.
To some extent they became gradually less prog. Lees started writing parody songs, Poor Man’s Moody Blues for example.
If you look at the list of BJH albums, it was a lot of work in a short time. There were also compilations and live albums. In fact, the live albums, especially the budget Barclay James Harvest Live, are good representations of the band, though no Wolstenholme songs ever feature.
In fact, Wolstenholme, possibly the key member of the band, was becoming unhappy with being in the band. He struggled to get his songs onto albums, and had personal problems, so left after the album XII in 1979.