Sounds good to me. If you're getting a builder to do it, you're almost definitely better off with whatever system they're happy using.
Everyone will have their preference that they feel most comfortable with.
Honestly, I reckon it's 6 of one, half a dozen of the other. Over 25 years, it'll probably do the same job.
Every builder I got a quote from recommended fibreglass over EDPM since we are going to have a roof lantern.
The builder I'm going to uses this system: https://www.tuffstuff.co.uk/
Sounds good to me. If you're getting a builder to do it, you're almost definitely better off with whatever system they're happy using.
Everyone will have their preference that they feel most comfortable with.
Honestly, I reckon it's 6 of one, half a dozen of the other. Over 25 years, it'll probably do the same job.