Same here , bolted through the cowl . or the bulkhead the original perspex screen fit into. It is a surprisingly robust aluminium section , could even be a casting ?
I fitted home made large aluminium washers on the underside for peace of mind in case someone uses excessive force on the screen.
I also fitted rubber rain strips in the slots left by the removed original screens.
These are shaped to match the originals below the cowl , and project 5 or 6 mm above it.
These work surprisingly well and stop rain coming off the bonnet onto your lap.
Do you have pictures of your setup?
