On Thursday, 10 January 2019 13:29:14 UTC, Bill Wright wrote:
Well, it isn't really gravel. It's limestone, mostly one inch lumps. The
limestone is a couple of inches deep, then there's six to nine inches of
rubble underneath. There's 187 sq metres. In places moss has grown. I've
killed the moss but under it the stone has a lot of soil mixed in,
somehow. I'll have to scrape all this off and put new stone down, but
how can I stop this happening again? I was wondering about waiting until
the dry weather and getting some sort of blow torch thing? Ideas?

Bill

The only solution is tarmac.
I have blocks. Weeds grow in the cracks, need dealing with twice a year.