Thank you all for your input.
Have had a look at the points raised and some of you might be interested in what I've found out.
More Than - I checked their excess policy. It is £70 for dogs under 9. For dogs over 9 it is £70 + 20% of the rest of the vet fees.
More Than and Greenbee - They do not provide the same cover. More Than provide £7000 per condition for vet fees where as Greenbee provide £7000 per year for vet fees, that is a huge difference. Personally on that aspect I would prefer the Greenbee policy however on everything else More Than is a better policy for me. The biggie for me is that Greenbee do not include homeopathy in with their vet fees, it has a separate limit of £1000 per period of insurance. There are other significant differences too.
More Than and Sainsburys - again these policies aren't the same. At surface both cover per condition (MT £7000, S £7500) but Sainsburys cover less under their "Vet Fee" umbrella and have separate much lower limits for certain things.
As always in these things the devil is in the detail. When I first got a dog I thought I'd researched insurance but I now understand that I need to actually study each policy to be able to make a comparison. I guess you pay for what you get. However what I'm hating is how much they catch you with a lower premium and then on its renewal it literally sky rockets.
With four that is no joke.
Looking at your responses and a couple of other cases I know I think I might of spotted something. In the cases I know of it appears that people with more than 1 dog on the policy have a lesser renewal rise. My other three are with Direct Line (I now know you can get better cover than that) and that doesn't rise too much so far though we'll see in the next few days when their renewal arrives. I could actually move Max who hasn't had any claims or illnesses so I'm wondering if its worth putting him with Morgan.
Have just changed from morethan. Last year Marley was 11.99 a month, this year it would be 15.99. We have never claimed and Marley is only 3 so i thought that was a big increase.
That said, i think what they offer is competitive with other companies. 
When you say "this year it would be £15.99" is that what they quoted you as a renewal or is that done yourself through a new quote on their website? I just ask because I'm discovered the two are very very different things which is very annoying and very unfortunate.
To anyone reading this who is getting a dog and will be looking to insure it I have one bit of advice......study the policies! I am very fortunate in that Max and Morgan have not had a thing wrong with them and have not visited the vets for anything other than vaccinations which means I can move their insurance about without any exclusions. The view to take when first looking for an insurance policy is that your dog is going to have to stay with that cover for their entire life. If your dog gets an upset tum, which they do from time to time, and you go to the vets you will not ever be covered for an upset tum if you choose to move your policy regardless of whether treatment was needed or whether you made a claim.
I am now driving myself insane with the ins and outs of each policy verses the cost of it. I'm very aware that this could be the last move they can make, not that there's anything wrong with them but you just don't know what's round the corner.
In about four years when my financial situation changes I think I will self insure.
