My wife is a vet nurse and recommends Pet Plan but not the budget policy. She says the intermediate policy is usually plenty.
Beware yearly policies as for example if your dog suffers an injury or illness within that year, then the following year when you come to re new your policy they won't cover that condition, other companies will not cover also as they consider it a pre existing condition.
Also stay right away from a company called E+L if you ever want your money back.
Pet plan seem to come out a little more expensive than the rest but never put their premiums up based on your claim. They do it on the area and I think it's been a good few years since they increased their premiums or excess. Most other companies put theirs up yearly.
Hope this is of some use to you.
His Vet Nurse Wife ( and no i'm not on commission ha ha)