Hamish,
I cant find the dipsys, or 2 Abu 6501Cs and around £300 worth of lures..not a happy bunny!!
Anyway, have you looked at Paravanes from Storm? I found them better than Dipsys as once a fish is hooked, or the bottom come to think of it, they invert and plane to the surface. GAC have them at around a fiver depending on size.