All test results are available on the web here: http://www.brisbane.qld.gov.au/commu...fety/index.htm
If you actually want something written that says its safe, then you will never get it. Not today, not tomorrow, not in 12 months or 10 years. So perhaps consider something else for a company event.
BTW. If they tested the dog off leash area it would fail miserably. Enterococci is found in the fecal matter of warm blooded animals, and I have seen plenty of dogs take dumps in that spot!