Thanks Zozozo and others
I've cracked the left hand bottom corner apart from 22d and made progress on the right hand bottom corner. Just 27 and 29ac and 25d to do.
The reason I couldn't get the composer at 18d for so long was that I'd put Aging in for 17ac even though I know you don't spell it like that!
My excuse is a very busy day emptying the contents of the garage into a temporary shed prior to the demolition of said concrete prefab garage on Monday. More to do tomorrow.