Customer helplines that use recorded menus that promise to put me through to the right person but never do - and being ill. Oh, and did I mention customer helplines :)
Whenever I am looking for a new recipe I 'Google it' I'm sure there will be 100's of watercress soup recipes out there, you can mix and match two or three of the recipes that appeal to you and then just add or subtract ingredients to adjust the carb content to your liking
I would guess that most watercress recipes will contain potato and or onion but Im sure you can find a few that dont.