The new light fittings I got use the same base as my old ones as they are simply 'British General' ones, but one slight difference is the base for the new battens has clips to secure the batten fitting. I left the old baseplates on and just wired the battens to them, making them the same as short pendants that they wobble if touched. The cover for the baseplates screwed over the same old base plates. It just needed the live and neutral wires going in. No way I'm unscrewing and rewiring new base plates just so these <£2 batten holders can clip in. They are supported from downward tension by the cover, but are simply loose and wobbly inside it like pendants. Oh also I only did 2 out of 7 fittings, 5 more to go so my lampshades can be flush with the ceiling instead of hanging down at head height.