Sadly not, the tax system is far less equitable than that. You stop paying NI at about 45k, so the rates are 13% from 8-12.5k, 33% to 45k, 41% to 100k, 60% between 100 & 120 k) then 45% over 120k.
I'm afraid you're wrong. Its 42% to 100k, then 67% to about 120k then 45%. You forgot to account for the last NI hike, and the tax free earnings withdrawal from 100k (£1 lost for every £2 over), which makes the effective tax rate suicidal - only an idiot would pay it rather than work fewer hours/days.