Sorry to have to disagree John - but I did the identical thing with
Shared Ownership Mortgages
It too reached page two on day one and is now on page one where it has been for 2 months. It took ages for MSN to index and when it did it went top on live.com and page one on Yahoo.
Initially, you are correct that it 'might' drop -but that is where sensible timed linking and adding content comes into its very own.
URL titles on short one page sites really does work.