Apart from a few more obscure pre-skinhead ones and the Beach Promotion one that came with matching trunks, all the skinhead period Ben Sherman buttons downs (from what I've gathered, looking at a LOT of them) have fully sewn in box pleats and 2 darts for a slimmer, more waisted look. As Brownie says though, they lost the pleat when the Beagle collars came in, whereas many other manufacturers kept their pattern the same from their buttons downs and purely changed the collar (retaining the pleat, darts, fancy sleeves etc), to continue to cash in on the popularity of the 'skinhead checks'.
Pretty much all the British button downs aimed at the skinhead market had full pleats (including Brutus, Jaytex, Arnold Palmer, Pagasus, Peter Gunn, Slimline, Slim Fit, Slim Jim etc etc, even the really cheap ones from the likes of Fine Fare!)
Yank versions (usually) had pleats at the top which faded out.
(American company) H.I.S. offered their "Neat-Pleat" (around '67 I believe) which was stitched in to the waist, then flared out for comfort. A couple of English makes copied this - would have to check which when I get home as I've got a couple from '69.
I just cant remember Ben Shermans with sewn in box pleat, but i do remember all the American imports i bought from the Squire shop, They was so cool at the time and most people never had em.