Career progression for a dental nurse 

i think it all starts step by step. First you get the diploma and then qualify as a trained dental nurse. Then comes the GDC registration. Then as the experience progresses and you do additional courses and CPDs your level also increases. Else if the dentist you're working under is kind enough to vouch for you on resume that you are well versed in few additional qualifications that works too I guess. Not sure though.

You have to be registered with GDC before you can practice anywhere officially as a dental nurse in UK. But, if you are enrolled in a dental nursing degree then you can practice as a trainee dental nurse without any registration.