"Round my way the hire compaines want to see your own insurance cert,
or insist on theirs."

I have never found that the companies near me request insurance at all.
They will merrily hire out plant and the onus is on you to sort that
out! Its a scary proposition really, as there must be lots of people in
a similar position that make "expensive" mistakes, only to then realise
its there wallet that then has to take the full brunt of the damage
costs.

The point about the plant training site that I got my CITB license is
a good one and worth a try.