There will be an extra letter in the wordplay and possibly no defn
13a Painful growth by Midlands venue, sound as a bell (10)
NEC in there possibly??
18a Old drunks lost at sea locate bottles in the end (8)
21a Everyone leaves river with local one married in nearby town? (11, 2 words)
Any crossers I have won't help as the answers have to be modified on entry to grid