Bulgarian/UK Citizen - Relatives work issues

I would appreciate a bit of advise on the following:-

I have dual citizenship and as Bulgaria is in the EU now but bulgarians are restricted with regards to having full rights of accessing the UK labour market I would like to know whether I can assist my sister who would be comming to UK shortly to obtain permission to work freely here. I have heard and read about form BR1 but to a cretain extend this does not appear applicable to this situation as I now have citizenship here.

Please advise of any options and thank you for the assistance.