I have no direct knowledge of them. I would be wary for the following reasons -
1. If they are charging almost the same rate as they are being charged by BT, how will they generate sufficient profit to cover their overheads and stay in business long enough for you to enjoy 12 months of use.
2. If they go bust after 3 months, what happens to your £150 (unused subscription).
3. If their web page is unavailable now (www e7even.com), what sort of availability do you expect their service to provide.
As I say, I have no actual knowledge of them - but having seen many 'unlimited access' dial-up ISPs go belly-up, I am wary about paying a year's subscription to any new start-up ISP.
There are many reputable ISPs that allow you to pay monthly, quite a few are only a pound or two per month more expensive. Shop around is my advice :)