Firstly there would be ruler lines on the edge of the note so you can measure something if you happen to have a note in your wallet. It would also have the phrase "ruler Britannia" written on it next to the ruler lines. Perhaps both sides of the note would have ruler lines. One side for inches and the other for centimeters.
Then there would be a table with 3 lines going down it showing every price between 50p and £50 divided by 3, 4, and 5 in increments of 50p
Like this...
Price %3. %4. %5
50p. 16.6p 12.5p. 10p
£1. 33.3p 25p. 20p
£1.50. 50p 37.5p. 30p
Where Jane Austen is there would be a rough map of Britain with all the main roads, I have nothing against Jane Austen, I have never read pride and prejudice but I'm sure she was a good writer. I just think a map would be more useful.
An animated hologram of the Queen would be on there showing the queen stroking her chin, thinking about all the nice features on the note. That would be an anti forgery fixture.
Then there would be all the swirly lines and fine print to make it hard to forge.
If there is space, there could be a conversion table. It converts Imperial measurements with metric ones.