Roger Phillips in his book "Wild Food" makes noyau with gin.
When I make it I use young beech leaves that have just burst from the bud, and still have the really vibrant green colour.
Richard Mabey in "Food for Free" also uses gin.
His recipe calls for the young leaves to be packed down in a jar and covered with gin for about 3 weeks, before straining off the liquid. Then, for every 500ml liquid, add 350g sugar dissolved in 250ml boiling water. Then add a dash of brandy. You should end up with nearly twice the volume of the gin that you used.