Recently installed our new to us kitchen which was made 5 years previously. It's a hand painted kitchen which I have added bits to make fit in our place as in a couple more units & doors and new cornice which I have primed with Zinsser bin 123 the rest of the kitchen was/is a cream colour which we are wanting to change to a sky blue.. My question is do I need to put the Zinsser primer over the whole kitchen or will a thorough rub down of the old facias and doors to give a key be enough for the new paint to adhere to? the Paint I am thinking of using is little green oil based paint. Thanks in advance for any advice.