In reply to francois:
We bought the double seat inflatable from Decathlon 4 years ago and it comes out each September for the DWS festival on the Costa Blanca.
Its great for this as you can seat 2 with seats or take them out and 3 can clamber aboard! Fits in a bag in the boot of the car, although a bit heavy to carry across a hot beach on your own!
I am just looking at getting another one as we speak to use here at Pembroke so if you find a good deal please let me know.
Regards Sam Orange