I can see where you're coming from here.
I'm probably what you may consider to be a yuppie, though I'm not exactly sure what that even means. I've lived my entire London life north of the river and before buying in BS never really thought about living south. I really like Champagne and Fromage and found the staff (didnt meet the infamous twatty guy) to be very nice. I think a lot of the restaurants in BV are good value for money based on taste and what you're getting. But at the same time, I like the produce and fish stalls too. In the 2 weeks I've been living here I have used them, although not as often as I would like (due to the hours they are open, etc). I've always known and been friendly with my neighbours and I don't expect that to change now that I'm in Brixton.
All I'm saying is, someone may look or dress a certain way, fit the yuppie cliche, may be new to the area...but that's doesn't mean you don't have the same worries, interests, etc. Well, with the exception of people with big status prams. In my experience these people are usually douchebags.
I'm not saying that you, the individual you, is someone who is ignorant or problematic. Individually, most of the newcomers I've met (those who've not shied away or snubbed us lowly locals.... seriously it has happened...) are nice interesting people.
One of my concerns is something that I think can't be helped: you have arrived in Brixton knowing nothing much about what it was like before. You don't know which shops are family run, or have changed hands, or are brand new. You don't know about the specific beggars and buskers (wither The Philosopher, by the way?), that strange influx of Roma in long colourful skirts who came and went over a couple of years, the Russian lady with the outlandish make-up and the towering black nylon hair, the local kids who were kicked down the stairs by the cops, the one who refused to take sides in a heated dangerous situation, went home to his mum, and thus, possibly, averted a riot, the fact that Patrick insisted that any restaurant run on his property must be vegetarian, that the Courtesan bar used to be run by an idiot who named it BangBang the weekend after a shooting, that the tree in Windrush Square used to have fairy lights all over it, that the Drinking School who used to hang out there is all gone entirely, that the land that was ripped up to lay Windrush Square was filled with interesting plants, some dating back to the banks of the Effra, that there is a rare example of kinetic sculpture in the garden of Lambeth College, that the old oak on Josephine Avenue apparently shaded the canoodlings of Sir Walter and Queen Bess, that there used to be a grand old squat on Porden Road that is now a car park, that the old clock in the park used to work tick tock, doesn't now, and is being refurbished by local subscription, that the little toy houses outside the secret garden, which have recently been fixed and painted, were part of a village that is now somewhere in Australia, that the Tesco by the prison used to be a great little venue... and so on and so on and so on.
This is not to say that I am precious about all this. It is to recognise that anyone who is new to an area does not know, and cannot know, what that area was like before they popped up out of the ground. When this is a few people, a few families, well they have the chance to hear and learn and join in and find out and bring their own stuff and on we go.
Right now, it's like we're being colonised. So many people all arriving at once, and all bringing with them the kind of culture that has deliberately and strongly stayed away from Brixton in the past, derided Brixton, dismissed and shunned Brixton as a place of danger and poverty and strangeness. And for many of us, one of the reasons we ended up in Brixton was exactly because we didn't find ourselves as individuals, as the people that we are, welcomed or supported by the people who shunned Brixton. We came here, some of us, to get away from that kind of snidey judgement. Outsiders, misfits, rebels, we all ended up here because here we felt comfortable.
So now we find that not just one or two pioneering curious interesting people, or families, are arriving in Brixton, but droves and packs of people who either drift through on a weekend, getting in the way of people who are doing their weekly shop and making ridiculous comments about how weird or lovely or
quaint (yes, really) it is to have a real life butcher opposite the vintage store... as if the butcher is the pop-up novelty, and then going home to wherever they've come from like tourists on a week's holiday in Senegal going home to claim that they really did get a sense of the local commuuuunity, such friendly people except for the strange angry ones, but who can blame them when they struggle so with the poverty and crime, bless 'em. Or they (you) are finding that Brixton is borderline affordable, so they're buying up blocks of property, that was sold outside of the community, like the Brits who arrived like locusts in the South of Spain in the eighties.
We, many of us, feel alarmed and disturbed by this. We feel sidelined. We feel as if we have been marketed as one of the charming assets of the locality.
This will pass. We are in flux at the moment. It will settle down. Not for a while yet, judging by how many
many developments are still being planned. But while our squatted arts centre, our college, our social housing are being taken away from us, from people who have lived here decades, generations, and tarted up to be sold to incomers, we are kind of edgy and mistrustful. Not least because no-one asked us about any of this. It has been done
to us,
to Brixton. We've lost a lot, and we're not able yet to see what has been gained.
Brixton Square: I'm sure it will be a lovely place to live, and I'm glad that you and yours have been able to get a toehold on the property ladder. I'm glad that Barratts have been decent and helpful, and I'm very glad they've bothered to plant trees. But every time I go past, I remember the CoolTan and the fun I had there, and how sad it is that we no longer have the place itself, and I am also sad that these days, we no longer have any option for such a place to ever exist again in Brixton.
And by the way, no one in France would ever eat cheese and drink champagne at the same time. It's madness!
YES we need a meet up 
