*No I think the Kate cut is not mumsy at all because it's long & versatile. It's the short cut pictured above. You know - I am married now, kids, need to be practical, don't have the time for regular blow drys/styles so I'll just cut it all off & I won't have to worry about it.
Hence the "Mum cut"otherwise all hair would be mum cuts!*
I see it the other way. That short cut is work to spike properly, and requires regular trims. If you dont have time and cant be bothered, the last thing you do is get a cut like that. To me, a 'mum cut' is no cut at all. Just let it grow, and you can ponytail it, curl it for dressing up, pin it up for dressiest, effortless day to day, but so versatile!
Or, a mum cut is the spikey one, about a month over due for a trim and root color. To olong to spike, and roots showing.