My understanding is the UK is switching to polymer banknotes, which have been in circulation here in Australia for almost three decades now. I can see how they might perceive the texture of the banknotes as similar to certain types of receipt, but the banknotes are noticeably thicker. You also have the see through window which feels very different to any of those things. Next you have the size: they're all larger than a receipt and certainly smaller than a flyer (and if we've done your banknotes the same as ours, each note is a different size from each other, 5s being smallest and 100s largest). Finally, the latest addition, the tactile dots would also give them away.

They may take a little getting used to given you've not experienced them before, but having known polymer notes my whole life, I've never known anyone to have issue with them.

I live in the UK and the notes are easy for me to use.

The 5 has no braille like dots on it and is the smallest.

The 10 has two braille like gs' on it.

I prefer the newer notes.

I believe the polymer banknotes also have raised print and “Braille-like” dots to make them more accessible.

Ie http://money.cnn.com/2017/09/14/news/uk-10-banknote-cash-plastic-blind/index.html