I had a look in Carrefour today and they've got nowt. You could use one of those tranciever things that let you watch your tv out in the garden while the satellite's in the bathroom.

Or you could google wireless cordless speakers. I found these websites:
www.withandwithoutwires.com - Online Price: £69.99  
www.home-gadgets.co.uk Price: £59.99

The first one won't deliver overseas, but the second will and they look much nicer anyway