https://www.amazon.co.uk/Arsvita-Bluetooth-Cassette-Receiver-auxillary/dp/B07WC1TYMV
How about trying something like this for £17?
I used to have the old fashioned cable one to plug into phone headphones socket, but this is Bluetooth
Plug and play out the box for less than 20notes.
NOTE: I've never used this one before, but it looks like a cheap easy solution