Insurance re Hire of Camper Trailer

We are hiring a camper tailer with annex for an up coming holiday at a beachside park.
Wondering about taking out travel insurance mainly in relation to those clauses in the Hire agreement, where the Hirer releases the owner and employee, agents of the owner from all claims, damages etc. and also where the Hirer agrees to idemnify the owner for all claims, damages and costs in respect of personal injury, property loss or damaged suffered by the hirer etc.

We are also to pay a bond of $500 which is the basic excess insurance (said hire trailer is fully comprehensively insured) this bond will be returned approx 7 days after trailer is returned in good order.

I note that one domestic policy I looked at will not pay for items I own left unattended in a public place, which I suppose includes our clothing, TV, Fridge, etc etc so I expect they're pretty much the same across the board. I realise its a different kettle of fish if you own your own van which is not made of canvas, can be locked and has been in use in the last 24 hours per owners van policy I had a look at on line.

I am most concerned about the indemity clauses however. There appears to be indemity cover on domestic policies to value of $5million. What this covers exactly am still to double check with insurer.
Any suggestions re personal insurance from others who have hired camper trailers in the past?

Thanks in advance.
Bernie.