Thanks Richard. The Genographic site says you can't (yet) transfer Helix co-branded kits, but if you used a Participant kit then you can pay to transfer your DNA sample to Family Tree DNA additional testing. I wonder how you tell if you have the Helix type kit or not?:
"For Geno 2.0 Next Gen Participants (but not Geno 2.0 Next Gen Helix co-branded kits) the raw analytical output from your DNA sample is available for purchase through our partner, Family Tree DNA. Go to My Profile, select the My Results tab and scroll down till you see Transfer my Results on the right hand side. Or you can click here.
For Geno 2.0 Next Gen Helix co-branded kit Participants, we are currently exploring options to be able to make this available to you."