You do need to do monthly thorough examination, and it should be done by a competent person and records kept, as below with my making text bold to stand out. Up to you to decide if that person is internal or external, but not annual.
Chris
From the regulations noted above
(3) Where respiratory protective equipment (other than disposable respiratory protective equipment) is provided to meet the requirements of regulation 7, the employer shall ensure that thorough examination and, where appropriate, testing of that equipment is carried out at suitable intervals.
From the HSG53
90 Maintenance is a requirement for all RPE, except for disposable (single use) RPE,
and should be carried out by properly trained personnel. Thorough maintenance,
examination and tests should be carried out at least once a month. However, if the
RPE is used only occasionally, an examination and test should be carried out before
use and, in any event, the interval should not exceed three months. Emergency
escape-type RPE should be examined and tested in accordance with the
manufacturer’s instructions.
91 There are five key points you should follow when carrying out RPE maintenance:
■ Follow the manufacturer’s instructions.
■ A competent person should carry out the work.
■ Keep records (see Figure 7 for an example).
■ Ensure the intervals for maintenance are appropriate.
■ The maintenance programme should reflect the complexity of maintaining the
RPE.