Or to put it another way, lets suppose I was to offer you £100 per week, but to specify that it was to be used for things that I consider good, say more veggies for the family and a gardener to create an outside space. Then offered some extra bonuses for a family holiday to Spain, but I didn't tie this into any formal contract, so I could withdraw the offer at any time. If this was to happen, you would reject the idea ?