That's the way it works and has always done - I realise that's not the answer you're looking for though!
You will however have benefited from the status miles above 54,000 being converted to destination miles, so 20,000 status miles will have become usable for redemption purposes (or at least should have - you're best checking that has definately happened).
As mentioned in this FAQ thread,
http://www.flyertalk.com/forum/bmi-d...yet-v-4-a.html
However, at the end of your Gold year, all status miles are zero'd and will not be carried in to the new year. The programme is generous, but not that generous.