Vol. 10 of the Visitation of England and Wales (1902) has Ernest Gabriel Boissier (b. 1886) as son of Rev. Frederick Scobell Boissier (b. 1854), vicar of Denby, Derbys. and headmaster of All Saints' Sch., Bloxham 1886-98. He was son of Rev. Peter Henry Boissier (1822-1880), curate of St Paul's, Clifton, who was son of Rev. Peter Edward Boissier (1791-1888), perpetual curate of St Peter's, Malvern Wells, Worcs. 1835-59.
Peter Edward Boissier is stated parenthetically to be son of John Lewis Boissier, of Bath, by his wife Dorothea Howard, dau. of Sir Paul Crosbie of Crosbie Park, co. Wicklow, 4th Bt, thus connecting these Boissiers to the families we treat here in some way. I don't have a copy of BLG 1965, but a search of that volume on Google books shows that Rev. Peter Henry Boissier (as above; alongside his role at St Paul's, Clifton is mentioned his being curate-in-charge at Barcheston, Warwicks.) appears in that pedigree, so we can safely conclude the connection you thought likely, Richard, is indeed the case.