Remember it's not about being covered in case you accidentally shoot a prize bull mistaking it for a Munty.
If you have people with you, or under your supervision or direction, and you send them to point A, where they slip and break an arm you need to be covered as an Employer. If you sub let, you need to be covered etc etc., hit someone with a vehicle while shooting, tear up some saplings you didn't know were there.
Write down all of the risks you run, and how people could conceivably balme you for them coming to fruition. Then look at the different policies.
The most important thing to remember is that if you supervise someone, even if it's your best mate, you can be viewed as their employer, even though no money changes hands - it's down to them having to act under your instruction.
Choose based on the insurance not the people providing it.
"I hate the BASC so you shouldn't use their insurance" is not good advice. Fortunately, for the people giving it they will never have to stump up the cash if you lose your home because you took it.
That's an awfully big risk they're happy to take with someone else's financial security.