After 8 months of going very slowly on the main house build, returning to work 2 days a week plus a bereavement has not helped, I am approaching needing the hidden gutter detail. The architect gave me some ideas but after a lot of discussion with some of my materials colleagues I have concluded that zinc / grp / powder coated aluminium wont cut it and I have decided to go for lead. It is a hidden gutter and having looked at loads I have come up with a couple of ways of making it happen, see section images below. I think I like option 2 as I don't have the phaff with very short roof tiled section at the eaves. Both have a slight problem in that cannot see a way of getting a through draft under the supporting marine ply. I also wonder if I should give up on the second, upper, over lap of the lead with the VCL and take the lead all the way up to the underside of the tiles, this saving a problem with an insect guard. Anyway thoughts appreciated.