
If you upgrade it'll be classed as a new policy anyway, so the current problems wouldn't be covered regardless.
Anything that you've seen symptoms for before cover is taken out or during the first 14 days of cover (10 days on Aviva) will not be covered, that's how they'll do the exclusions.
I would wait for now and find out what it is - the last thing you want to do is change policies then find out it's going to cost a fortune to treat. Trust me, I've done that thinking a condition would be fairly cheap as in the vast majority of dogs, it is (thyroid). It now costs me a small fortune to treat and test because in that dog, it's a very unusual form of the disease so he needs different medication which is not cheap!