From the flower shape I'd go for Ladysmock but I'm not convinced by the colour (a bit on the dark side) or the flowering season.

Yes but never heard of those flowering in autumn let alone all winter, just for a few weeks in May.

it reminds me of Virginia stock an easy to grow annual. they last about 6 weeks, self seed and then if left alone the seed germinates grows, flowers etc.

flower arrangement and leaf if wrong for Cardamine pratense

I'll go with that SBG. can't make out the leaves - it was right at the back of my mind that this was something really common but Ladysmock kept coming forward.
Looking up Virginia Stock, it seems to be very easy to grow (almost weed status) but I can't say that I've come across it that often. I remember my mother buying seeds more than once always with a resigned "I'll try it again thus year" with the unspoken "I don't expect any results"

Virginia stock was the first thing I sowed when I was about 4 and many years afterwards, and it never failed. Must be something to do with the soil because it certainly wasn't green fingers!
This does look more like it than like Lady's Smock which as Urbanite says is usually much paler, and is also usually rather taller and more fragile looking. But VS usually has a variety of shades and these are all one unvarying one. Its a puzzle.

you can get single coloured seed now for vs. it was my first success again at about the age of 4. Dad encouraged me to sow seeds very few weeks. I was hooked on genetics when I tried to find out why some flowers could be one colour on one flower and a different colour on another, all on the same plant.

I am now convinced they are Virginia Stock planted by the birds and survived a very mild winter