BMW Financial Services and PPI

I have put in a complaint to BMW Financial services as I was advised by the sales person that I would have a better chance of being accepted for the finance deal if I took out the PPI. I included my signed purchase agreement with my complaint which clearly outlined I had PPI.

BMW Financial Services have responded acknowledging I have PPI but state that "you may not be aware that for claims in contract, the cause of action accrues on the date of the breach of contract and a six year limitation period runs from this date. The agreement commenced in May 2003, so any alleged misselling would have taken place on or before this date, therefore the limitation has expired."

They suggest that if I want to pursue this complaint that I should contact the dealership and that I may not have the right to refer this to the Financial Ombudsman?

Has anyone else had this experience and what can you advise?

Many thanks