Forgot to mention snow, normal roof netting will not withstand heavy snow, and your cage roof must be very substantial
if you intend leaving netting over the winter. We have pigeon netting under the roof netting and it's been OK so long as
we go and knock the snow off if it gets heavy.
Knowle Nets site is new to me, they didn't have one last time we bought from them so look under fruit cage /parts for
the netting you need.
Did you see my previous reply to your first post about making the structure from galvanised steel waterpipe and
keeklamps - kinder to the netting than wooden posts and stronger than Ally tubes.

Rod