No, you didn't see BKS leathers on WJB, but you did see MJK
They are available off the peg or made to measure and it'll cost you about the same for a made to measure suit as it would for a standard suit from the likes of Dainese (about £800-£1000 the last time I asked depending on spec)
They're made in Holland I think, but their UK distributor is a company called GLF Factors in Flitwick, Beds (opposite the railway station and about 40 mins from Kings Cross Thameslink). Graham, the owner is a really good bloke and really knowledgable about racing and all things to do with what it takes to make good racing leathers. I can't afford any yet, but I'm going to replace the old Spyke with a set just as soon as I can.