Oh dear....
Answer one question raise another

OK so the speedfit pipe should be fine with the polypipe panels.
but....
Brandon, you say the PP is more flexible than the SF, is this based on the PP being polybutylene and the SF being Polyethylene? SF now do a PB pipe which I was planning on using precisely because of the increased flexibility.
Also if I don't use SF or PP manifolds, who would you recommend?
And what pipe would you recommend, if not 15mm PB?
Cheers