I'm approaching it from a slightly different angle. Spending now to get house, garden, vehicles, in best possible condition so that when we both qualify for state pension in a year we shouldn't have too many demands on our savings at that point. And house could go on the market quickly. Mortgage has been paid off for a few years.
Otherwise living more frugally atm to get a feel for just how much we spend unnecessarily. It seems that £3k monthly gives us what we consider reasonable, and driving it below that might become a bit miserable. DH and I each have one luxury which we would hate to give up, but could if necessary. That would probably give an average of £2k monthly.
Recently we've had to spend hundreds on glasses and teeth. Plus by choice going privtely for biopsies, etc, just so we know what we're dealing with.
Away to do some sums now.....