What is a British English equivalent to 'Fussbudget'?

Fussbudget noun US informal, old-fashioned.

(UK fusspot)

a person who is often not satisfied and complains about things that are not important: "I can't eat this meat - it's too tough." "Stop being such a fussbudget and eat your dinner!"

(Cambridge Dictionary)

Fussbox is another AmE variant:

(Southeastern U.S.)

a fussy or needlessly fault-finding person Also called: fussbudget

(Collins Dictionary)