1 Across, Judge quantity of metal reduced in 13's work (5)
4 Across, 13's work recalled girl in second swim (8)
8 Across, Holiday period indicated by 50 leaving early? (3,4)
11 Across, Flitting, old Scotsman sure to change 13's work (6,8)
Many thanks sheneystar2, Terry Pratchett is not my type of reading really, Just Googled him and I did not realise he has written so many books, anyway many thanks again.