My apologies - always read the question first!! I was distracted by having a P60 in front of me..... which was scary enough. The original question is a very difficult one to answer, as so much accrues to Mr B @No 11. But not all PN, I suppose you would have to allow for the amount your wealth in terms of goods and property had increased (less the amount a future Chancellor would take from your heirs).
Reminds me of a Budget Day remark made by Robin Day many years ago, in anticipation of a so-called "giveaway" budget.
RD: "All this talk of the Chancellor "giving back" so many millions is of course rubbish. What may happen, on very rare occasions, is that a Chancellor may decide to take less!"