I have never seen a fridge that is big enough, only fridges that dont have enough food or beer / wine / spirits in them.
You should run a tape measure around the cavity just to be sure before buying a fridge,just to be sure it will fit and your 900mm(for example) is stil 900mm after you have moved in. The skirting board may take up 10-20mm at the bottom and you are unaware of it and can be easily caught out.
Alos generally the condenser is at the rear of the fridge and any heat generated from it will rise and emit from the space between the top of the fridge and the top of the cavity. Some extra space around the fridge would help with some airflow though