As a RPWE candidate, we basically assess if you will receive proper exposure in your current place of employment. A person might for example be a security guard at the NPA but might never receive exposure to most of the learning objectives and outcomes.
ALL students must submit the portfolio and logbook AND supporting evidence as this is the only way in which we can assess if you receive the needed exposure and can "do the work". So, use the assessment criteria to guide you in compiling your portfolio.
The competency certificate is basically proof from your employer. Only current information in your current place of employment is needed.
Hope it helps!