Hi, we moved ours about 2 years ago from inside the house, under stairs to outside as we wanted an under stairs loo. It was around ?900. It actually was fairly easy to arrange. We had to contact Southern Gas Network (I think that was the name - got the contact from our gas supplier). We just booked a slot, with 3 or 4 weeks notice. If I recall correctly they won't provide any new pipe work in your house so you have to arrange for your own plumber / gas engineer to come that day to make sure it all works. What I would say is we thought it was going to be a total nightmare doing this but in the end it really was not (except for the price).