Well, John, if 15a is easy - then I'm thick!!
Robert, re 12a think of a long distance runner - going back a few decades or so! Also another word for encourage for the surname.
But, I agree with you both on personality clues - if you don't follow much tv or radio, one's reduced to trolling through the RT listings - at least that's what I do!!
Managed to complete 3/4s in half an hour, but struggling with the last few - will perservere!