Quite an interesting piece on the BBC suggesting that 3G may be effectively standards under the new building regs.
including a new type of 3G called "Architectural Technical Glazing' - U-value ~0.5 - with a very thin centre pane, which is supposed to make it more practical as a 2G replacement.
I'm not completely convinced, since glazing is only one aspect and 2G is available at a U-value of under 1.
As ever, imo it will be down to how to meet the minimum requirement at the minimum price.
https://www.bbc.co.uk/news/business-67161076