On the subject of crimping.
 

I have to connect three radiators to new plastic tubing. The tube is 16mm
pex-al-pex. The plumber is bloody useless and wants to do an ugly lash up.
I'm proposing to use 16mm crimp connectors to 10mm compression fittings
then 10mm copper from the wall to the rad valves a fairly short distance.

Rads are triple panel 3kw each.

Has anyone used these crimp fittings? Any difficulties? And will 10mm be
adequate bore for a large radiator? The run of 10mm should not exceed 40cm,
may not even be that much.