The locking issue on these Yeoman Telescopic Bypass Loppers is so annoying that whoever designed this equipment I'm sure cannot have tried it out for more than a short while.
My experience of equipment that can double up (long and short handled in this case) is that they do neither function well.
Do not buy this unless it's a gift for somebody you aren't keen on.

I bought a pair of Yeoman Telescopic Bypass Loppers at a local Garden Centre, for £21. I asked a knowledgeable member of staff about the loppers, and he mentioned the telescopic adjustment could go wrong. I had not had this problem on my previous pair, so Ibought the new ones.
They are good in that they easily cut 30mm green stems and branches - BUT the "simple click of the grip end to extend or shorten to the required length and to lock in the chosen position" is a nightmare.
The adjustment is incorporated into the end of the grip, where it naturally falls against the heel of one's hand, so they unlock almost every time you cut something, or even if you put them down on the ground! This makes them almost unusable, and very, very frustrating indeed!
A good product rendered almost useless by a dreadful design feature.