Surely a call to the company would confirm what the requirements are.

i would expect something like "your main address" to feature somewhere in the T & C's.

I think you need to speak to your insurance company. It's far better to tell them exactly about the situation rather than just make guesses as to what their requirements could be.

I can't see them wanting a repeat admin fee in the situation in which you describe but, as I say, it's best to ask them and tell them the whole story.

I don't know how the two areas compare in terms of insurance rating but you may-well find that if the B16 is more highly rated thsn the BR6 one there could be an increase in insurance premium.

Thousands of drivers must spend a lot of time away from their recorded residential address. If it is hard to decide which that address is, pick the cheapest one .... :-) Could get awkward if you need to claim when parked overnight at the 'wrong' one, but the main thing is to be insured.

Log on to the insurance company website and get a quote for each of the two addresses. If the new address will be cheaper then email the insurance company and tell them that the new address is your primary residence but that you also stay at the other address regularly. If the new address is dearer tell that is the primary residence but you also use the other address sometimes. It is up to you to decide which is your primary residence and the amount of time you spend at each may vary from month to month or week to week. It doesn't depend on where you spend the most time. If that were the case then oil rig workers would be resident in the North Sea.

If she owns one or both of the premises then there may also be capital gains implications depending on which she decides is the primary residence. To bolster up the claim of one residence being primary she can make sure she is on the voter roll there, get her car tax and driving licence at that address and do all income tax correspondence from that residence. If home ownership is involved it can have big financial implications so be sure to think it out carefully.