"The health and safety manager then instructed him to climb up the racking which is 2.5m"
This instruction alone would indicate to me that the H&S Manager is incompetant but, at the same time, the Agency Guy should have refused point blank to expose himself to such a risk?
Work-related injuries to self-employed people on your premises, and near miss incidents that occur on your premises, must be reported. Just call the Incident Contact Centre on 0845 300 99 23.
If you are working in someone else's premises and suffer either a major injury or an over-three-day injury, then the person in control of the premises will be responsible for reporting, so, where possible, you should make sure that a) they know about it - All they have to do is call the Incident Contact Centre and answer a few questions about the incident.
Or b) do it online yourself - https://rweb1.nbapp.com/hse/riddor.nsf/F2508DO?OpenFrameSet
Whilst I fully appreciate the precarious situation we are all having to deal with in today's very iffey financial climate, there's no excuse for so-called H&S Managers, 'knowingly' submitting anyone to a risk situation.
Get on line or on the phone my-man.
Regards
MVM