In reply to Tom F Harding:
I've had good customer service from BD. Got some replacement parts for a pole sent without and questions. You do have to pay for the shipping to the UK though.
I had the alu foldey ski poles, can't remember the model. They skied really well. I left them on the roof of my car one day. =[
I use the BD Trail poles for hiking, summer and winter. Super stable. one of them slips a tiny bit on long descents, it slipped 5cm over a 6km descent where I was putting a lot of weight on it. But the z-fold ones have the metal flicklock adjusters which seem slightly more robust.