Out here in Egypt we don't get kippers, but we do get bloaters - ie. herrings that are smoked for a short time but are not cleaned before smoking.
As we use these in Kedgeree (there not being a great source of other smoked fish here), I buy them whole, then top and tail them, slice them open and remove the guts and bones.
Quite a simple process, but I find that in most (if not all) of these, there are 2 smooth, creamy portions in the belly of the fish, one on each side. They look to me to be roe, but it's hard to tell as the smoking has removed any resemblance of eggs from them.
Does anyone know herrings well enough to clarify what these lovely-looking areas of possibly edible niceness could be? I've tasted them raw (smoked) and they could be roe, but I think they'd be better being pan-friend to finish them off.