Here is the chart I reference when booking BMI award flights. http://www.united.com/page/article/0,1360,1185,00.html The only time I book an award is when I want a business class ticket as in the past I was able to get away with more carry on in biz. There isnt much cost savings a lot of time in booking an award as opposed to revenue ticket as the ticket on BMI's site is something like 5GBP and the rest of the price is in taxes and fees. The taxes and fees for an award are quite high especially since you are talking about a 45 minute flight. I am surprised they quoted you such a high price unless travel is tomorrow.

Oh, good idea on the booking so you can track it. I would email as well.