How to clean stinky becko drip tray from inside fridge? ?

We have the 'dead body' smell coming from our Becko fridge! after looking at this site it's clear its coming from the drip tray and we are thankfully not alone in experiencing this!!
However ours is an intergrated fridge and the fitter had real issues when fitting it and had to fit extra brackets on the door attached to side of unit as the door wasn't holding properly so due to this we can't get the fridge pulled out to access the drip tray!
So please any advice on how we can clean it/ break down the milky gunk I imagine sitting there? I have been pouring boiling water down the hole which makes the smell subside for a bit but hasn't made it go away!
Any tips appreciated!
Thanks