I have a lovely big wardrobe of tailored work clothes in size 18. I am however a 12/14.
And then I have lots of clothes to collect children from school on a bicycle with.
And a small collection of v random clothes I've bought to wear out, in the last couple of months, some of which fit.
Oh, I have a v weird smock type thing, dungaree thing, with a skirt, that's short and black and quite sweet, that I could wear a fitted tshirt under. It's cute. It might fit.
Oh, and there's a lovely silk dress with silk-screened stars all over the skirt, purple and blue. Very nice. Quite norkish (strangely, as I basically have none), made bespoke for me. When I was a size 18. Might work, anyway, though ...