The Bank of England said 775 million paper banknotes remain in circulation. 113 million paper £5 notes remain in circulation 73 million paper £10 notes remain in circulation 360 million paper £20 notes remain in circulation 209 million paper £50 notes remain in circulation https://www.bbc.com/news/uk-wales-60763998 £500 of that is with me in New Zealand
I thought it was also interesting that in addition to the paper cash, the Royal Mint said about 105 million old-style £1 coins have not been returned. I only have £5 of those £1 coins, and regret selling off about £20 of them some years ago.
I have quite a few. I ended up with so many £1 and £2 coins. I had a big 1L beer stein filled with change when I left.
All notes issued by the MOD were demonetised so it would not include BAFSV or BMA notes. All Bank of England notes issued since the founding of the BoE are still exchangeable.