Life means for the life time of 48, so as long as the company exists or even if its taken over by another company the contracts apply. That doesn't mean that you might want to leave yourself if the service is not up to standard as happened when they launched this originally. But 48 are offering the same deal to any customers who left and want to come back. Personally Id be happy if it lasts a couple of years its easy to move to another provider anyway.
