Rob,
Having consider your situation, I think your still have a good chance of getting something sorted as I don't believe from what we've discussed, that what has happened is a fluke thing. If they have not prepped properly and simply sprayed over the other top coat, then they are guilty of mal-practice. If the job was never done properly in the first place, then your claim should stand regardless of time.
If the job was done properly and this has happened, then you would have no chance, but I don't think that is the case.
I think you should get it checked by an independant proffesional. If they never did the work properly in the first instant, then you have a right to claim.