Hi Puzzled, I'm off to bed in a minute but can spare you a bit of help before.
I took ages to get the theme with this one.
The 14a is crossing with modified answers but the letters to enter are 3 of 5 of a word that means a Corolla.
36 - word for 'went back' as Hair does
42 - anagram , Scottish hillside
47 - Think of a film about a vampire with a very famous black actor (made three film trilogy)
Down
8- Is off is the Def, sleeping
20 - word for 'True' with a bit missing
23 - anag of siege & sex
35 - a kind of produce (veg) / Two letter word for adequate + two letter name of a God
Hope that helps, Les40