does anyone know roughly when a cocker spaniel should reach their full adult weight? My 11 month old bitch is still around 9.5 kg but seems to be at full height despite having a healthy (dog food and few dog treats) appetite during the week and being spoiled by my mother every sunday!

Hi,
I know it's probably not the answer you were hoping for (sorry!) but there isn't really a fixed age when the adult weight is reached. If she is her full height (about 15" according to the standard, but of course you get larger and smaller examples in every breed) her correct adult weight will be whatever is correct for her particular build - which is often slightly less than what they weigh as adolescents. (It's generally better to put the weight on slowly than fast.)
Hope this is remotely helpful.
:)

http://www.canineplanet.co.uk/cockers.htm
Go tot the page i have posted above you will need to cut and paste, there is a lot of info there