There's another stage you can go! The plastic moulding the pod fits into can be removed from the boiler casting. You need to rotate the moulding about 15° clockwise on the boiler using a bit of leverage between the trunions and the moulding both sides. It's rather stiff but once turned it releases a sort of bayonet fitting retaining the moulding to the boiler.
Inside there's another ‘O' ring, that can be suspect for a leak, and a plastic sleeve behind it.