I think its all a bit of a con? They make you buy at least 6 bottles at about £10+ a bottle (for cheap wine) then charge you P&P unless you order a minimum of £80 to try and push you to order 2 cases, what ever you do you'll probably need to pay £30 out of your own pocket when you'd probably get 6 bottles of a similar quality from tesco for £30 at least then you can pick them up when you want and not have to be in when they're delivered. that is assuming you really want 6 bottles of wine?
I'm not saying its a completely crap idea I'm sure it works well for many people or you wouldn't have all these wine companies. but its one of those situations where you lead to believe you're getting a good deal when really you're no better off than if you went to the supermarket