Hi @LittleMissUnreasonable
I think you're right and I notice a lot of women from abroad who've made the UK their home have continued their 'glamorous' lifestyle here.
With regards appearance and looking like one has just stepped out of a magazine, I would venture the following...
The key thing seems to be about being consistently and impeccably groomed: hair, eyebrows, nails (clean, short, neutral colour)), a bit of 'natural' make-up. Clothes always clean, well-fitting, which starts with having the correct underwear, clothes tend to be close fitting, straight lines, all body parts covered (nothing hanging out) neutral colours. Having the correct shoes, outerwear and accessories curr the occasion and the rest of the outfit. All of these items are kept in a good state of repair, never any hint of fading/tiredness. Inevitably these women (and men) generally lead a healthy lifestyle with regards weight management and they make very conscious and consistent choices about the quality and quantity of food and drink they consume. They also all appear to have lovely teeth.
These women (and men) appear chic all the time, whether they're on the school run, on play dates, at the weekend, during the day - always impossibly 'put-together'.
To look this good all the time takes good routines, healthy habits, being organised, and a desire to always present the best version of oneself.
My mother-in-law, born and raised in Salford, Manchester is exactly the same in terms of adherence to being well groomed and well turned out. Her fashion choices are completely different and hair, nails and makeup also conform to a different aesthetic, however, she always looks put-together. This isn't a British vs Other world thing, however, I do tend to notice friends and associates raised in other countries tend towards to being more fastidious about this way of showing-up.