Independent Insurance, a UK based company offered cheap insurance a few years ago and went belly up, leaving policyholders with no cover, although they had paid premiums.
I think that it is always better to deal with an Iriah insurer as if there are problems, you have a better chance of having it resolved.
do not be guided solely by price. it is only one aspect to consider. Amongst others, you should consider policy conditions - is there average, new for old, increase in sums insured at Christmas/wedings?
Claims procedures also need to be considered - is there a strict notification time and if not notified in that time span, will claim be refused? is there a local claims handling/investigation sevice?