6. What conditions can we place on a purchase contract?

If you are dealing with a dishonest vendor, there is not much comfort in having a contract which says he promises not to cheat you.
So you need to know who your seller is. And make sure all possible concerns you may have are addressed as conditions in the contract and alleviated before handing over your money.
Alert Property Group recommend you use a good solicitor who specializes in business conveyancing to prepare the contract, and a reputable Accountants to conduct "Due Diligence" prior to completion.