Yes that's my thought too, @NMC2022 - watch out for the pre-existing conditions exclusions. It will likely exclude anything he has ever been treated for or tested for.
Worth asking your existing insurer if there's anything they can do on price? Not sure what your current excess is but it may be worth taking a bigger excess if funds allow.
Even at £60/month plus your excesses I'm friending Ollie costs more in an average year, otherwise I'd usually suggest self-insuring if you have savings or access to cheap credit. I'd never suggest the same for pedigree cats (ask @toddlerteaplease)