https://www.theverge.com/circuitbreaker/2019/9/12/20862236/ikea-cheap-sonos-remote-control-date-price
The small controller works like this: Push it down once to pause, again to play; push two or three times to skip tracks forward and back; or rotate the dial to the left or right to decrease or increase the volume. It works on a table or wall thanks to an included magnetic mount.
https://www.ikea.com/fr/fr/p/symfonisk-telecommande-volume-noir-40433780/
Works with any Sonos speaker according to above IKEA page.
You also need the Gateway @ £20 so at a total cost of £35 this seems like a steal compared to the extortionate iPort Express product.