We have 5 between my daughter and I. My 3 do what your describing. My oldest, Yogi I had in and out of the vets when he was a baby convinced he had a ct. and he had every test for this and it was ruled out..My 3 have it worse when its allergy season, and when they are excited. The little one Suki, does this more when she is playing hard and running. Reverse sneezing is so very common in these little guys..I was at my best freinds this morning and she has a 2 year old male Maltese and he was doing the same when I walked in her house.
If he appears as this getting worse rather than the same, I would take him to your vet and have him take a look just to be sure. The only thing that sounds different and concerns me about your Kipper is has to lay down to recoup. Are his eyes watery or is he scratching alot???Was just thinking of allergies?