Add Fixed Price Meal Deals as a Discount Option

[ScottBrown2198]

It would be handy to have a discount option that allows for deals such as "2 courses for £20" or "3 courses for £30". This could be done by selecting triggers which are either individual items or categories (tickbox function to select 1 or multiple of those types) then a fixed price, variable or fixed discount could be applied (i.e. set total to pay as £20, take £5 off, or take 5% off).

The discount will only trigger if the triggers have been selected on the bill. This should be available to use on a bill more than once to allow for multiple asking for the same promotion.