Note that under IAC 07/20 of 20 September 2007: 

Employer registration 

1. Individual occupational registration is not necessary to meet the policy requirements of SM19.5 and W2.10.1(b)(ii).  There are instances where an employer holds an “Employer Licence” (i.e. for Electrical registration).  In such instances, an employee who is offered employment with an employer who holds an “Employer Licence” is not required to hold individual registration to undertake the employment offered.   

2. An employee who is not registered but who is employed with an employer who holds an “Employer Licence or Registration” meets the policy requirements of SM19.5 and W2.10.1(b)(ii).