I would suggest that you check with Pet Plan, but you have committed to an annual policy, so I would have thought that it would be unlikely that you could cancel with no charge.
But, whilst Pet Plan are expensive I wish that I could afford them for my dogs (and would in the future have less dogs so I can afford to insure them with Pet Plan). But if you are going to change, just check the wording of any new policy. Not only do you want life cover but places like Sainsburys for example offers 7k per condition (so not per year) which would never have covered Jacob's HD. They also increase the price as the dog ages, so Jasper is with Sainsburys and I currently pay £97 per month with £125 excess plus 15% of every vet bill. Thats a lot of money just to insure him!
Jacob is with Axa and they offer 7k per year which is better than Sainsbury's but I still have issues around how they work out claims!