As for you not being registered with the WRS, your employer could get in trouble for employing without all the correct paperwork.
It's up to a £5,000 fine for the employer and all work up to now does not count towards the 12 months qualification period under WRS. You are supposed to rgeister within one month of starting a job but not before you start a job. The employer is supposed to provide a written confirmation of the job but the repsonsibility for registering lies with the individual.