David - I have been to some of these places. I remember Glencoe and Fort William, but it was back in the 1970s! I looked you up because I've just bought one of your books - A Season for the Dead - and can't wait to get into it. It's got to wait a bit, because I'm very busy right now promoting my forthcoming novel According to Luke, which takes place in Venice, Ravenna, Malta and Damascus. The photo I can see here on your page takes me back to when I was researching the locations in 2008.
Since I live in Western Australia, it will be a while before I can research my next novel, which is still an embryonic WIP which starts off in Rome... the reason I bought Seasons, and because it looks like it's in the same genre.
I'm going to follow this blog, and read your archives by and by. Have you read Days Without Number by Robert Goddard?