'70s yes, but the first car to use a BW65 was the Dolomite and it was the only one to use it until a few years later. Somewhere, I have a period motoring mag with the Dolomite's launch featured and, as was usually the case in those days, the advertisers all got in on the act with ads that featured their contributions to the new car: Dunlop Groundhog tyres, Brico Metals for the camshaft, buckets, shims & valve seats, Southern Bros of Bolton for the seat frames, Coventry Hood & Sidescreen of Telford & Bedworth for the seat fabrics, Callow & Maddox of Exhall for the finished seats, Burgess for the exhaust system, Formula of Gravesend for the steering wheel, Alford & Alder for the front suspension components & the steering rack, Metzeler of Peterborough for the rubber to metal bonded suspension and subframe bushes, Holroyd of Rochdale for the valve guides and some manual gearbox parts, Girling for the brake components and so the list could go....
Anyway, potentially far longer story shorter; Borg Warner's piece in the mag states that they
were proud to be associated with the new Triumph Dolomite and were delighted to be able to supply its maker with their all-new type 65 transmission
before said transmission would gradually be
made available for use by other manufacturers.
So in other words, every owner of a pre-HL**
Automatic Dolomite was, effectively, a guinea pig for BL and many of the world's other car manufacturers.
**The launch of the HL badge coincided with other BL among other makers' products beginning to be fitted with the 65 in place of the 35, so it suddenly wasn't exclusive, not when every bugger else could have one.