I'm with NCI on a lifetime plan.
I insured Will and Nancy when they were 3 and it was £8 a month each.
At renewal last year Will's went up to £10 and Nancy's to £12 as I had had 2 claims for her for the same problem (not huge amounts).
Renewal is due shortly so I'll report back on their premiums for this year as they will be 5.
Will isn't covered for 'unexplained ' gi stasis but if it is the symptom of another illness it may be covered, depending on how the vet reports I guess.
I had no issues with Nancy's claims.