You can use your CO Miles to fly to London Gatwick (maybe have a short stopover in London) and fly from London Heathrow to Reyjavik.

Alternatively, if you've done London before, fly London to Glasgow (there are some really low fares on British Airways) spend a few days in Scotland and fly Glasgow to Reyjavik.

Look at www.icelandair.com
www.britishairways.com

Whatever you decide - have a good time! Iceland's on my wish list too!