Ok, I've got some time to waste waiting.
Some impressions, all the raffia bags were in the sale, seems no one wants them anymore. Everyone seems to be wearing their phone on a special chord like these and depending on whether they're working it's with a leather crossbody or a fun recycled market type tote if casual. With bank cards now on phones, I guess this was a somewhat predictable evolution. Only ever saw the ubiquitous Uniqlo bag on tourists, 'le banane' seems to have had its day here. Also at 28 degrees everyone still stoically wears a jacket but at 24 after the rain has passed it's camisole time 
Also, I forgot how much Parisians love a platform sandal, they've taken to them way more than I've seen elsewhere. Does anyone remember the Bocage shoe brand, they were huge in France at one point (15+ years ago, I guess) they were sort of overly rounded bulbous platforms, I thought they were hideous but much loved here despite my opinions on them.
Otherwise, Paris is as lovely as ever.
My buys, I've bought another pair of The Row sandals 
at a cracking discount. I've always loved the idea of white sandals but never liked white leather or the sort of clunk all white can make of your foot so these are perfect in a way I never knew I wanted/needed. Quite comfortable despite looking so flat, they have some internal cushioning and rubber heels/pads. Apparently they were a runway shoe and were worn with £££ tabi socks, not sure I'll be buying those but I'll try and see with some Muji ones.
Also bought, this silk Toteme tanktop which promptly got worn the next day with linen trousers. Although those pictures don't really do it justice, my The Row sandals are also ten times prettier in real life than the above link. Might be a theme here.
I found some jeans proclaiming to be carbon neutral, which helped as I usually prefer not to buy denim new, these are also a huge chunk lyocell (40% iirc) but feel like 100% denim that's slightly worn in. Bit of a relaxed tapered style to ease me into the inevitable gradual move away from wide legs and probably more practical with rain. Brand is Boyish, I'll have to look up which ones they are exactly.
Then this Helmut Lang top which has a bit of a cold shoulder thing going on, so by the rules of S&B you're all supposed to hate it.
Then this top but in a different colour (see pic, only pic I could find of it). Thought it was a French brand, going by the name but turns out it's South Korean. I love the colour and cowl necks are ridiculously flattering on me, plus 80% off, how could I resist 🤷
Other than that I got some really nice makeup bits, a Kjaer Weiss bronzer at a ridiculous discount. I've always admired the heavy compacts with refill aspect but never took the plunge. For shame, the bronzer is instant rich bitch has been on holiday perfection. Also got a really lovely Nars lipstick at 60% off. Red, naturellement.
Not on sale, I got this dress from a Polish brand (they have an Amsterdam store too, really must check in more often). It's the perfect 'holiday I don't want to wear anything, it's too hot dress'. Yes, it's a rectangle with some elastic in but that little split does distinguish it somewhat <clutches at straws> and the fabric would be difficult to source, the texture really made it. It looks better on me without the straps (they're detachable) so I actually did find a new way to wear the strapless revival, with a cleavage window...
Then things I did not buy but am hopelessly coveting, because, insane prices, but this probably enough to plough through already. I'll find some pictures maybe to torture myself and share here.
And as mentioned previously, the secondhand shops have gone rogue, so that wasn't fruitful.
WRT London dates, those look fine, any odds on when the Matches sample sale would coincide with one of those dates.