Smg gear change problem e46 2003 m3

[manutd25]

Hello all, having a problem with that good old SMG system. Warning light is on, and it's getting stuck in certain gears after a 20 gear changes or so & depending on how hard I drive it...(on tip toes at the moment though). Starting to make a louder click/clunk when changing now as well. Can't hear the priming noise either on unlock. I've changed the relay, & had it diagnosed twice which indicated the gear position sensor was faulty. Having read so many posts about the pump failing, I don't wanna change sensor as advised by the bmw specialist and then find out it is the pump,...as I would then already be down £450. Please has anyone got any advice and does anyone know a good warranty company as I don't wanna go through this nightmare again. Cheers.