In my experience, insurers are more concerned when a property is located in an area which has a history of regular flooding.

What happened in Llandudno was a one-off 25 years ago and has not happened since.

That's tempting fate Bri, they said something similar about the floods in Llandudno Junction and then put some flood defences in and said that a flood would happen only once in a 100 years.

Unfortunately I think that it flooded again the following year

I'd make two points: the first is that probability is an interesting branch of mathematics, and, although it does, indeed, even out to the predicted outcomes over time, there's nothing within probability that says you can't have seven very bad flood years in a row. It's exactly the same as flipping a coin, where the probability of heads or tails is the same - 50/50 or 50%. However, it's often possible to land several heads in a row.

In the case of the flooding, so long as you only had a couple of events during a 200-year period, they could be in adjacent years.

The second point is that it's been long known that the incidence of extreme events will increase as global temperatures increase. We know that global temperatures have been rising steadily for some years and one interesting consequence of that for us is that our climate will become wetter and colder.

But Bayesian probability underpins the entire science of meteorology and it's been shown to work pretty well. Insurers are supposed to work from Bayesian probability but base all their costs on statistics and hence epistemic probability.

So in short, don't bet on there being no repeat of lousy weather...