I did quite a bit of research on this when we obtained our two and in the end opted for LV Pet Insurance's Premier policy. It has a £5K per condition benefit with no time limit providing you stay insured with them. Gracie's policy is £7.50 a month and Monty's is £8.50 a month and the reviews on them were pretty good too.
UK call centre too which is a bonus!
Good luck with whatever you decide :smile: