Thanks Puzzled Badger, I tried that but then I'd messed up one double cell so got nowhere. If you turn the shape made by the lines on it's side, you get a Halloween themes object.
I've tried those lines but nothing happens for me. I start at LM; that has LU in it. I go to LU and that has OX. There's only a D at OX but if I continue the line I get to SY, which has NI. I carry on but end up nowhere, when I should finish at LM.
Much obliged muraria and christamac. I always scan a copy of the grid with puzzles such as these and it paid off this time as I made a few wrong double entries in the process. Toil and trouble indeed.