Muddymike wrote:
Is there anything that actually kills moss and prevents it returning 6
months later? We have a long tarmac drive and large back yard that is
20% moss covered!

Mike

Ferrous Sulphate keeps my garden moss-free for a very low cost - it
kills the stuff within a day - but it will cause iron stain on
light-coloured stone/concrete. I expect dark tarmac would be okay.