Thanks for your reply John! The second one was brand new - only fitted 3 months ago, but as with the first one, I think poorly fitted with the jubilee too high, so it blew off in the recent storm.
The front two chimney pots had rain cowls fitted to them 3 months ago.
The second one back blew off in the recent storm. It looks like a part snapped off, but that was there already - the cowl itself is intact.
The first one looks like it’s clinging in for dear life. Have these been fitted...