Nige,
there are undoubtedly many, many incidents of which there never was any record - especially if ground fire didn't make contact. There are others, a few within my own experience, where the nature of the operation meant that details of any kind will be sparse or non-existent. Neither of these helps you particularly, but the anecdotal evidence may still be available from some of us older Alberteers. Whether anyone would listen is another matter... Nevertheless, seems like you're getting quite a lot of verifiable info anyway!
That said, it might be worth looking into books about the Beverley, Hastings, Andover and others for historical evidence of the dangers of small-arms ground-fire. The idea that there could have been a relatively cheap protective measure against this risk up to 40 years ago is galling in the extreme. It's long overdue.