AIB did good for me, not a full timer but guess they do it.
I have looked into this and so far I can't find any insurance company offering unlimited overseas insurance. Furthermore, if you are a UK home owner, as sure as eggs is eggs your house insurance will be invalidated if you are away from it for over a set period of time.
My question was more about how they can have unlimited time in Europe...
Nothing to prevent it... yet.
Safeguard used not to impose time or mileage limits, but have had to change underwriters. While I believe that there are still no time limits, at least one of the underwriters appears to impose mileage limits that might be restrictive.