I agree with everyone's comments. M & S has always been my go-to store for clothes, for both quality and fit, not to mention easy returns, but I struggle to find anything I want these days. I too, am a shorty - only 5 ft, and their shorter length trousers used to be the right length, but about 5 years ago they suddenly got longer, and I would still have to shorten by several inches if I purchased them.
I get almost weekly offers on my Sparks card, but rarely find anything to buy, not for want of trying!
Fabric quality has gone down, styles are either ridiculous or boring, so no wonder they are in trouble.
Per Una needs to go - all those frills and furbelows have had their day, younger buyers certainly don't want them, and the Autograph range isn't very inspiring either. (Years ago, they had an Autograph Weekend range, with a more casual slant, in lovely fabrics, but that was discontinued - I still have a few tops from that range).
They need to accept that the younger generation isn't interested, and aim for an older clientele who are looking for good tailoring, better fabrics, and competitive prices.