I got a second hand 10w non focusable hid umbilical off ebay for £180 inc delivery. It's the best thing I ever did.
Keep a look out, you could get a bargain. Just seen one on ebay, four days left to go and it's a salvo one, current bid £100.
Salvo 10W HID umbilical dive light on eBay, also, Dive Lights Torches, SCUBA Snorkelling, Sporting Goods (end time 11-May-08 22:04:09 BST)
Cheers
Lyv