All answers have UK place names in them.
12) This actress and her daughter both appeared in Playboy, 21 years apart (5,9)
13) Writer with a mountain, a lake and a square named after him (4,6)
17) A martyr to the cause of liberty (7,7)
18) At the age of 18 he entered Boatwrite University to study writing (4,3,6)
22) A mechanical mastermind with a particular gift for making useful gadgets out of ordinary rubbish (9,6)