Hi Tony
I dont think anyone at all can say for definite what you will lose...like the other said, average 1stone for women, 1.5 for men.
There are many factors to build in, again, they have been covered; how much to lose, and whether you are doing exercise, etc and what you are drinking.
Dont compare to others; you will lose what you lose so long as you stick to it 100%. Dont put too much pressure on yourself; the diet is hard enough without saying you need to lose "X" amount each week; you may just feel dissapointed sometimes.
Like Elle says, check others tickers, but again cant always be an indication you will lose the same...you may lose more!! Who knows.
Have a great week