Anto_ie,
I faced same issue…when I arrived to UK.
When I arrived to UK I got only EEA family permit, myself and my husband went to register they GP told I can’t register myself, as I got only 6months valid visa. For them it’s not longer enough to prove as a resident. Only my husband got registered as he live for a long time and he is EU citizen. At that time we didn’t care that much about it.
We thought EEA2 would come in few weeks. Then I can register with GP with longer visa. And I applied for EEA2, and started waiting for EEA2 arrive. Then I started reading this forum EEA2 doesn’t come soon. At least it will take about 8 months and can’t live without registering GP as well.
Then I wrote to the local NHS PAL (Patient Advice and Liaison Services (PALS) ) the difficulties in registering with GP. After few days she asked me to go to the same GP, this time they register me without any question.
http://www.nhs.uk/chq/pages/1082.aspx
So I recommend you to mail your local PAL. Explain your case and tell about EEA2 delay. They need to resolve this issue. GP always refuse to register, if they see 6 months visa.