Thank you both PS and Brendan
I realise I have been to both places: the one I was thinking of - a small city - and the right answer, though the latter had a different name when I visited it back in the 1970s.
I'm panicking a bit as I spent a lovely afternoon visitng a delightful garden in the middle of Devon - so, so tranquil. And I still have lots to do. Beck was good. I read the books once, but that was back in the 70s as well and I can't remember the plots. They only wrote nine books. (Sjowahl and Wahloo)
Further hints required for 5ac and 12d. I can only find five words that fit the letters I have for 1ac which are ?P?R?A. Hints for this one would help. I've never been to Scunthorpe!