Thanks all, yes I did sign a contract with the hotel for the rate. Unfortunately it says "Event Planner" on it. But I didn't realise what this meant.

However I did make it VERY clear in several emails to them beforehand that "I also want to pay in full upfront and make all charges/points to one master account on my HH profile." and subsequently "Please confirm that the total will therefore be $5406 and all the points will be allocated to my HH account."

I'm going to appeal to the hotel, who I believe may be able to apply some discretion here.

Thanks again!