Yes, my 2 girls are insured and yes I have claimed and yes I'm glad I had insurance!
The vet bills probably weren't that much to be honest, couple of hundred pounds, but it was nice to have the protection of the insurance which allowed the vet to perform a couple of investigative procedures to try and find out what was wrong (which failed to discover anything of major importance, sadly) but we still had that cover so they could do what they liked and knew it would be paid for.