"an acrylic piece of knitwear from peacocks is going to look shit, though, after a oucple of washes, innit"
Agreed. But at £14.00 it wouldn't be the end of the world. The Warehouse one in the OP already looks like it's spent a week on the floor of my teenaged son's bedroom. If you hand wash cheaper (wool-a-like) items and dry flat they usually turn out ok. Machine washing them is generally the big no no.
Choice of colours at New Look.