In article o.uk, Dave
Liquorice writes

Mind you anyone who gets a ticket on the shiny new double yellows can
contest it and win, They have changed a single yellow to double but
not the signage. Where the signage actually exists that is, some is
just a grey post or a yellow plate with nothing on...

I think that has changed, double-yellow lines now mean "no waiting at
any time" by default and don't need upright signs to go with them unless
to qualify them in some way, eg as seasonal.
--
fred
BBC3, ITV2/3/4, channels going to the DOGs