We are in conveyancing now, so waiting to see whether our purchase (in the 500-925 bracket) is affected. I don't particularly approve of cutting SD right now given the likely inflationary effect, but like pretty much everyone in the world, would not object to having a bit more money at a time when every penny I own is getting tunnelled into the house buying process.
We certainly wouldn't ask our buyers to pay more than the agreed purchase price now, and I can't imagine our seller would do either, but I can see why people might be worried that this could happen in some cases before exchange.