I think some of the figures mentioned here would see you house bound most of the time and not being able to afford the things retirement is for, to really enjoy yourself.
Mad if you think about it, graft your arse off for years, f***ing your body (for those with physical jobs) and then just scrape by on enough money to heat your homes and pay your bills when in your 60’s!
If mortgage isn’t a consideration at an age to retire, then I’d recon an income after any tax of around £36k, around £3000 a month should be a nice target. £1000 for bills and around £500 a week disposable income, but more importantly your body needs to be in a state to actually enjoy it.