Thanks OM. I have soaked overnight in bicarb and seems to have done the trick. Not easy to discard as part of the freezer. Its one of those trays you fill and tip into fixed dispenser below.
I have found this a problem in the past too. There, the freezer was one with the dispenser on the outside door. We rarely used it as we always seemed to have smelly ice.
Any idea's what actually causes it?
There was a thread on this a while ago.
If any food/leftovers have ever been stored in the freezer the ice trays will pick up the smell. Frozen pizza included. The minuscule droplets that form and then vapourize through slight thawing/refreezing permeate the plastic. No amount of soaking the ice tray will fix it. We don't use the "built in" ice tray for this reason. One (labour intensive) solution is to keep the ice trays out of the fridge unless you are actively freezing a batch of cubes, which you can then store inside a ziploc bag.