My house is a 30 year old version of that and a lot less polished. On a large housing estate. But it is band G as will be many of the houses on this estate. The problem is the current banding puts houses worth £500k in the same top bands as houses worth £1M plus in my area.
DH and I are coming up to retirement. Our council tax bill is already nearly £4k a year. If it doubles and then increases from there by the time we receive our state pensions then roughly the entirety of one state pension will be needed to pay the council tax.
it will have a disastrous effect on the housing market.
I hope it is just another idea being floated by a think tank which will not materialise.