Well, that was horrible! Needed a great deal of recourse to this site, and even then it was a struggle. Found the NE corner especially arduous, not least because of shaky definitions and indicators in 6D and 10A. Plenty of obscure connections, too, especially for non-UK solvers - cover, heath, airline, slippery sort, etc. As Chrise pointed out the other week, it's too often a case of insert anything that fits then parse the clue, rather than vice versa.