Under European law, you do not need to obtain documentation confirming your right of residence in the UK if you are a national of a country in the EEA
However, if you want to support an application for a residence card by any of your family members who are not EEA nationals, you must demonstrate that you are residing in the UK in accordance with the Immigration (European Economic Area) Regulations 2006 and are 'exercising Treaty rights' in the UK. You are said to be exercising Treaty rights if you are:
employed or self-employed; or
studying; or
economically self- sufficient (meaning that you have sufficient funds to support you without requiring public funds); or
a jobseeker; or
retired; or
someone who has had to cease working in the UK owing to permanent incapacity.
UK Border Agency | Residence documents for European nationals
If that helps. My understanding was that if you have a EU residency or ideally passport you are entitled to work without condition in the UK. How complicated would gaining citizenship in your current country be, if you have been there since 2005 I would assume you qualify?