Went to John lewis to get new scales. its a minefield out there. There are some that record your weight so you can have different profiles in the family.
Mum - 11 stone
Mum - on one leg 10 stone
Mum breathing in - still 11 stone
Mum after a kilo of potato - 22 stone
In the end i went for the cheapskate ones http://www.johnlewis.com/150910/Style.aspx - they measure in incremenets of 200g fgs - so every single cube of chocolate will count.