Hi,
Sorry to hear your cat is so poorly. I’m a vet, I’ll try and help a bit with your queries with this, but only the vet hospital will be able to fully explain everything, it’s impossible without your cats history, notes etc to know why various things have been done.
With a consultation fee of £450 it sounds like your vets have advised/sent you to a referral centre - these are places which will have specialist medics, neurologists, anaesthetists, nursing care etc, so the cost of an anaesthetic here isn’t necessarily comparable with the cost of an anaesthetic for, say, an X-ray at your local practice. £1400 does still sound more than I would expect for just an anaesthetic, but depending on how long your cat was under, what was done etc, it may be about right (often there is a cost for induction, and then a cost for ongoing anaesthesia time etc).
unfortunately, £4K limit is very low, as you may now be realising. If I’m referring a neuro or medicine case, I’d generally warn it will likely be £3-4K+ for cons/imaging and then treatment/surgery etc would be on top of that.
Pre authorisation from insurance companies can take time to come through, which often is difficult in cases which need treatment urgently. Even in cases that they have pre authorised there are sometimes things an insurance company will decline to pay (based on their small print etc) and the responsibility for the bill always lies with the owner. Unfortunately we have had to stop doing direct claims as if insurance companies decline to pay, we end up having to chase owners who are reluctant to then pay, often to the point of having to involved debt collectors - which then impacts our fees for our clients who do pay up.
having said all that, they should have been keeping you updated with costs, generally with an update each day. If they haven’t, query that with them and it’s put you in difficulty now and ask about any chance of payment plans etc.
how’s your cat doing now? FIP can be a difficult condition to treat, with often a guarded prognosis unfortunately.