You'll find loads of insurance information on the "Insurance" child board which is just below this "Health" board in the main menu.
Lifetime insurance is by far the best option and I'd recommend £7,000 as a minimum amount of coverage as vet bills, especially for the more specialist procedures, can be eye-wateringly huge.
Our two are with Animal Friends insurance and I've nothing but praise for the service we've received but there are many others out there, each with their good and bad points.
Bob.