Hmmm. Thanks for the replies everyone. It had occured to me that I could 'sell' the service to the next tenants until it finishes, but they would then be in the same position that I am when they start a new contract. Otherwise they won't be able to get a line put in anyway it seems. How annoying that the internet world seems to assume that people live their lives in neat, 12 month blocks.
Ginger