JBV

I installed this today and the current plugin install doesn’t have this fix in it. I applied it and it now works. You need to update it.

I have exactly the same issue. No updates done to the site. No new plugins.
https://www.prickleshedgehogrescue.org.uk/

I can’t even log out as there is nothing but the menu.

That worked fine, thanks, think I’ll bookmark this for future upgrades as it seems it regularly goes daft.