We are trying to fit a new fridge into an old kitchen recess. I've read that we need 25mm on each side for ventilation. My question is: Can we go less 25mm between the top of the fridge and the overhead cupboards if the cupboards do not go all the way back to the wall? There's an open space of about 8cm between the back of the cupboards and the wall. Would a 1.5cm gap be ok given there'll be ventilation from the shallow cupboards? Thanks