Whirlpool frost free leak

I know this is not a “how to” forum… but 😳
Have a customer with a leaking Whirlpool frost free FF.
While repairing a dishwasher a couple of months ago, she asked about her FF and i advised to defrost. It has been ok, now the leak is back. Sorry have no model no but it is the type with a small box freezer on top of a larger fridge.
The water is dripping from the vent at the front top of the fridge.

trying to take one of these apart a couple of years ago i damaged the lining and only now go out on Hotpoint and Zan/Elec Frost free stuff.
Is there any common probs with this range leaking into the fridge?
How easy is it to access defrost channels / heaters?

Thanks for any tips
Sharp screwdriver Graeme