If you look at the front page of www.jurawatches.co.uk it says that a Bremont Supermarine is £500. Looks like a typo.
That's typical; build your hopes up then shatter them
It's a sneaky technique to get to the top of shopping searches. I've also had a few ads pop up on various websites for similar watches for £500, which makes you click then you see that it's just a deposit.