Sorry if this has been asked before BUT what is the maximum height a screen can be from the scuttle top to the top edge of the screen before it has to have wipers, washers and demist etc or is it not as simple as that? Could a rear view mirror be mounted directly onto an acrylic screen of this type or does it need to be on the scuttle top?

It's been answered before too.
If possible leave the screen off completely for SVA
Use a £5 suction mirror on scuttle, then decide what you really want to do after your pass.

My reason for asking is that I want to make up the mounting frames to fit on the scuttle sides so that I can mount my mirrors in their final place on the frames but I will fit a final, full height screen in place at a later date. I did do a search but couldnt find anything.

here:

screen poistiion