This has just appeared on GoMog...

WATCHPOINT: CRACKING 4/4 WINDSCREENS
There has been a rash of unexplained cracking windscreens for 4/4 Sports made since 2010. Owners would open their garages in the morning to find their windscreens cracked! Though these claims were settled by the company under warranty when they began, the Factory transferred warranty decisions and dealers were then instructed to refuse the claims and refer owners to their own car insurers. But iIrregardless of who pays, a backlog for heated windscreens quickly grew to three months. Happily, after two years the cause and cure has been found.
The 4/4 Sport uses different windscreen pillars from other classics. It curves slightly to accommodate the width of the screen. This part was newly made for the model and the curvature was thin enough to allow unfortunate flexing and therefore act as pressure springs when tightened. Replacement pillars, stronger and thicker at the curve have been made and this has (hopefully) resolved the problem. Replacem,etn 4/4 Sport windscreens are now delivered with the new pillars. (Make sure they are when your screen breaks!)

Link here....


Richard
1976 4/4 4 Seater