with your start weight given on your profile as 321lbs - you would need to have lost just over 32lbs to get your club10 - (i.e. weigh just under 289lbs - 20st9lbs or to be on the safe side - 20st8.5lbs should get you there).
Basically - it's 90% of your start weight - convert stones&lbs to lbs and then times it by 0.9 to get the figure.
yup the others are right...... your start weight was 321lb so it is 321 divided by 100 then multiplied by the percentage you want ie, in this case 10!!
As the merecats say..... shimples!!