Hello Uselesman. Not yet - the work (to cut the upstands) has yet to be done. I will post a comment here when it has been and let you and others know what effect, if any, it has on the problem.
Interesting thread - which lets me know that I am not alone - you can add Dorset to the list! We have a new extension which has a large (35 - 40 sq m) GRP flat roof with a 3 meter by 1.5 meter lantern in the center. This roof makes a lot of very loud bangs and cracks! It seems to me that this...