Here’s a question that Spike Millican lobbed at me to lob at the Post Office. He wrote (on 10 October) from S&A Superstores in Uttoxeter: “You might want to ask them why they are so far behind on converting their cash machines for the new £10 note. We only got told of our date, 27 October, after the notes were issued. Hence we have no £10 notes in the machine.”

The reply came back quick enough. “With regard to the new £10 polymer note, Post Office ATMs are all Wincor machines, and these require an engineer visit to convert them. All 2,665 cash machines will be converted by early November.”

This didn’t cut much ice with Spike as he already knew that. He retaliated: “The question is why this hasn’t already been completed. The ATMs have ‘Post Office’ emblazoned on the front of them. Barclays probably use the same engineers, as with the £5 notes, but I bet they wouldn’t allow their business to be detrimentally affected by such an issue. Or am I being unreasonable? They’ve even threatened to fine us if we don’t comply with the date the engineer is booked in for. That’s rich.”

Here’s a personal PS to the new £10 note. Remind staff that they feel just like fivers - so they need to look at them as well. My other half went to our local store with a new tenner and was given change from a fiver. He knew it was a tenner because it was the only one he had. Staff looked in the drawer again and was quite surprised and went all “sorry, sorry”. Those notes can be slippery devils.

The old tenners will come out of circulation next spring and the Bank of England says it will give three months’ notice of the date.

Meanwhile, retailers are in a good position to check out the serial numbers of any new notes that might be worth trading in because they sport variations on Jane Austen’s ‘statistics’. Look out for: JA01, Austen’s initials; JA75, because that’s Austen’s birth year; and JA17, the year of her death.

Serial numbers 16 121775 and 18 071817, which would represent Austen’s date of birth and death respectively, might also fetch you a small fortune.

Serial number 17 751817 includes her birth and death year combined. And 28 011813 was when Pride and Prejudice was first published, so might also be worth more than the value it technically represents. All those numbers come to you courtesy of the Hull Daily Mail.