Depending on how long you are away for, and hence your UK residency status, will also play a big part; very difficult if not resident for tax purposes.
I looked at adding life insurance cover a couple of years ago, generally things went smoothly till we got to the summary: "so, let's get this straight, you are a helicopter pilot, you work and live in Nigeria and you are no longer resident!"
Nothing off the shelf available, some kind Lloyds outfit offered term assurance for 165 GBP per month for 100,000 GBP cover. Thanks but no thanks!