Denying roof access to lead thieves without killing or serious injury
Anti-climb paint a) doesn't work b) gets on our kid's uniforms. Sentry guns are a favourite option within IT and DT, but implementation will probably be frowned upon by Plod. Catching them so far hasn't worked - Plod is unable to prosecute/apprehend for various reasons.
Deterrent is the aim.
I want something that either makes it impossible (or sufficiently unpleasant) to access our roofs that they're discouraged long-term. I doubt needle spikes on the wall-facing side of drainpipes is legal though.
What else is there? - the roofs are slate and the main issue is broken tiles and leaks when it rains. This is costing us a lot to fix.