If the wipers are coming on by themselves it sounds like a fault in the BSI. Common problem is water ingress through wiper scuttle panel/bulkhead.
Sitting in the drivers seat, put your right hand down to a removable panel at the bottom of the dash just right of the steering wheel. you will see a black box (BSI) with fuses in it. If it has water in it then it will need replaced. Unfortunatly will require genuine part and coded/configured by dealer
GW
May 2010