Got my taste buds going so here it is for anyone that wants it.

4 tbs lemon juice
grated zest 1 lemon
4 tbs olive oil
1 heaped tsp grain mustard
1 clove garlic
1 tsp rock salt
back pepper

Crush garlic clove and salt together in pestle and mortar. Gradually whisk in all other ingredients and pour over new potatoes whilst they are still hot (so they absorb it). Scatter with chopped chives and/or parsley
Brilliant with salmon or any other BBQ meats.