LOGICA2ME - You're right, just checked, I can place a controlled risk (guaranteed stop) for ARX online with IG Index. I phoned them and they told me it was borderline due to the share price, but they are currently taking bets. They are also doing KWL by phone, which is one they were definitely not doing a few months ago.
Incidentally, which is the best option; a daily bet with auto rollover, or a monthly / quarterly? I'm not intending to day trade this one, so it could be weeks / months.