Hi @Londoner78
I live, work and volunteer in Westminster, so it's my stomping ground.
If you are looking for close by, like a walking distance you may consider the other side of Vauxhall Bridge which is called Pimlico Triangle. This is the road across the gas station, near Barclays. It joins Wilton road and so on. Around this area is the daily fresh market, which also includes a fishmonger, fresh fruit and veg as well as daily takeaway food. There is everything you need including a DIY shop, Tesco, Waitrose, post office, a variety of restaurants, bars and ofcourse a large Sainsbury and Argos. You simply have to take a walk around this place. It then leads you down to Victoria station for the parents to connect for work. Lots of things to do for DC in general.
If you want to go towards the Senior school, going towards parliament, then there is a little market somewhere around Horsefery road. You have all the amenities and shops like Tesco and Sainsburys. But Victoria road seems to be the main place to go with cinema, theatre etc. You are still a walk away for both schools.
For Belgravia, the best place would be near Elizabeth street, which has everything and just a spitting distance from Vic stations. So walking to school. That part is really village like and will give you everything till Pimlico Road. You have easy walk to both St James and Hyde Park either way. If you live further up, closer to Hyde Park, no problem either as you can easily get a 5 minute direct bus to the Victoria or Vauxhall Road area. All the while being close to the big shops near Harrods. If you have smaller DC, the place is heaving with good pre-preps.
Chelsea is ofcourse the ultimate in 'village feel'. Especially Kings roads.
The beauty of WUS is that its one of those schools that are ultimate centre of London schools. Students come from everywhere. So it could be Kensington, Notting Hill, Camden, Lambeth, Oval etc. There will either be one bus that puts you right next to the school on Vauxhall Bridge or Victoria station, or you just need one change or a direct tube line.
If you identify a place or two, let us know and maybe we could say how you get to school.