It would be nice if we could refer to a job with a reference number. If an Employer has posted hundreds of Jobs he should be able to identify each job with some sort of unique Job ID or reference number

Agreed. This component could be re-written to allow access to every page with one or two component-related arguments in each URL query string.

For now, using advanced SEF will give you a URL like domain.com/view-job.html?jobcat=59&jobid=3