I read recently that Jaeger is going very well for M&S, it is mostly online and had very good adoption. There are some articles around in the press about it.
I was given two M&S shawl collar, cotton cardigans at Christmas which seem very decent.
I tried on a ‘Shetland’ crew neck in Fenwicks in Kingston. Various colours on offer, thinner than most of the ones I have at home, but still reasonable quality, saddle shoulder and fitted well, reduced down from 80 odd quid to 39. But made in China so I steered clear.