I have the theme - if it's as simple as it seems - 18 is a clue. But the acrosses are driving me mad - without definitions they could be anything. 10 may be an unlikely man's name made up of earl and s (for son) but then it could be all sorts of other things - and leaves verious possibilities for 2. If 25 is to do with railways, we are putting something in only to take it out again .... and as for 12, 15, 24 and 27, I'm baffled.