Thanks for everyones input
I ran yesterday with the Alloy front shock mount and the B-spec shock tower and didn't suffer any breakages - and had a couple of "offs" that were at least as bad as the ones that broke the car the previous week.
I also turned my shock mount screws round as suggested in earlier posts by Nick and Roger.
As a final thing, and not certain whether necessary or not, I boiled the plastic parts for about 5 mins and then left to cool naturally in the water.
So far, so good