My late mum used to work for Sirdar typing out the knitting patterns back in the late 40s early 50s. Like many at that time she made a lot of her own clothes, and carried on doing so thru the 60s and 70s. During this period she amassed an enormous amount of sewing patterns. When she passed I found a box full of 1960s / 1970s patterns. Some you can see are pre 1971 as they show shillings (1/- = to 5p) others show they are in yards instead of metres.
The UK started transitioning to metric in 1965, with decimalisation taking place in 1971. After James Callaghan the then exchequer announced in March 1966 that £sd would replace by decimal currency.