Thanks Harry. That's very good advice for the future. As it happens I've just bought an old 'Franconia' S&B 6x42 from Germanyicon. It's the right age-bracket, dimensions and reticle, has a 26mm tube and it's elevation-only, so in theory it ticks all the boxes and it was cheap enough not to be a disappointment if I don't get on with it. I'll see how that works, but if it doesn't do the job, I'll certainly try eBay.de.