Whilst we don't require you to have a return flight ticket booked, our underwriters state that in the event of a claim you may be asked for proof of your intention to return to the UK within the term of the policy.
Details of acceptable forms of proof of intent to return to the UK can be found here:
http://www.go-walkabout.co.uk/intending_to_return....
If, in the event of a claim, you will not be able to provide anything from the above list as proof of your intention to return to the UK, we will not be able to provide you with a policy. We believe that World Nomads might be able to provide appropriate cover although we would suggest contacting them to confirm suitability:
World Nomads
http://www.worldnomads.com/af.aspx?affiliate=go985348