They are in store now , I think they were last weeks special but they have loads left so have been reduced.
They are twist lock so if you open the fully then you will be able to slide the tube right out,but it pops back in and works fine,so not sure why that would be a problem.
I have locked mine at full extension and with my 18.5 stone leaning on them ,they don't budge at all.
They are apparently Nordic walking poles (whatever that is) so whether they are any good as trekking poles I have no idea,but for £7.99 they make good adjustable basha poles.
My local one on Marsh Barton Exeter has them in stock.
The other thing I bought was a pair of pocket binoculars as I was very impressed by the optics,and if they break, for £5.99 I am not worried.
GS