Chris J Dixon wrote:

Has anyone actually done it, and if so, with what materials and
effectiveness?

From photos where flashing exists on roofs, or copper has been added,
the copper seems effective (and other metals but less so).

I had to chop-up my second ladder (it was wooden and starting to get
weak) so now don't have anything to attach my roof-hook to, otherwise
I'd get up there and string a few runs of copper wire back and forth
along the ridge, I should have done it when I replaced the aerial.

Moss seems to have got worse in the past five years or so, I've heard
some people put that down to better air quality letting it grow, but the
anti-diesel mob might disagree with that ...