I had the same experience when trying to buy my S3 from a main dealer, I was in the same boat, big deposit wanting to place an order right now. They couldn't care less. I suspect they have quotas of the lower volume cars like S and RS models, and they can sell their quota at RRP so if you mention a discount they go cold very quickly. Even if that's true it doesn't explain the almost rude level of disinterest I got.