Hi, I just got back to this and am enjoying it so I don't want to see any answers yet!
But I can't see what 15A can change into, because my 5D and 15D crossers don't conflict with my answer for 15A. So the only thing that can change is the last letter of 4D (which I haven't got yet) - but that doesn't make a word out of 15A.
For anyone who's finished it, am I on the right lines with 15A? anag of FELONS + XI in the middle, meaning things that bend
And is it the 5th letter that changes?