My memories of 33's include seeing Dutch ones running in pairs on Meldon workings, Railfreight Construction ones runing in pairs on Channel Tunnel workings so there is logic in selling them as pairs.
For me though, I have enough 33's (2x 33/0, 4x 33/1, 3x 33/2) mainly due to the Hattons bargains that were for sale last year. Will still be tempted when they come out though!