Grapes and Watercress salad

I fell in love with fruit-leaf-cheese salads few years ago when I had the watermelon-feta cheese-arugula salad at Prost. I might have tried every outlet in Bangalore that served the salad - some nice, some a feeble attempt to just bring it to the table. My best was at Big Brewsky, until the restaurant got busy and didnt get the measure of the ingredients right anymore.
Funnily enough, this is not the receipe of the WFA. It's something I invented on a beautiful spring afternoon in Ingrave, UK. The reason I can confidently take credit for the invention is simple - I looked it up on Google and didn't find anything remotely similar.

Receipe: For 1 person
16 grapes cut in quarters/halves
A palmful of Watercress
A palmful of mixed baby leaves - spinach, red chard, lettuce (avoid iceberg)
1/4 Red/white onion Or 1 shallot, cut length-wise
1/4 orange/red bell peppers, cut length-wise
2 tea spoons grated cheddar cheese

Dressing:
2 tea spoons of lemon juice
1 tea spoon of white wine vinegar. In case the ingredient is missing, add 1 tea spoon of lemon juice and 1 tea spoon of water.
1 tea spoon of olive oil
Pinch of salt
Pinch of fresh ground pepper
1 tea spoon of water

Method:
Mix all the ingredients, but the cheese. Once the vegetables are coated with the dressing, sprinkle the cheese and toss the salad a couple of times.