I have the medium cover from PetPlan - £42 a month and £7000 cover per year. Used it a LOT over the last year and a half and have never had one problem. They are really good and I highly recommend them, but they are expensive (and Brodie is only five!).
One thing I would look into with the higher cover is if you need to pay a percentage of the claim once your pet reaches a certain age, like you have to do with the cover I have.
Same here - only ever made the one claim for Ozzy when he was 4 months old and had to have his left eye removed - they paid up straight away, direct to the Willows where it was done. We also claimed for our usual vets fees connected to the eye problem, which we had already paid, so that come straight to us. The total was about £2,500 I think.
We insured Ozzy with Petplan as we were really pleased with them. Our last dog, a GR called Cassie had epilepsy, and, although I have never added up the amount they paid out over the 3 1/2 years she had it until she died, it was a huge amount, including specialist fees for a CT scan, and accompanying appointments. By the time she died at aged 5 her medications alone were costing over £200 a month and that's not counting the cost of her regular vet trips and blood tests - they always paid out without a quibble. The monthly insurance premiums were under £40 by the time she died, but I'm sure they would have increased quite dramatically as she got older. The cover was for around £5000 a year for each illness then, I think.
We pay £32 a month for Ozzy now, although the cover is much higher of course. If you can afford the higher premiums, I'd always recommend Petplan.