Offeror and offeree are perfectly acceptable - don't listen to Profesh! However, you would do best to go with the terminology used by your lecturer. Both sets of labels are used widely in cases, but in the wider common-law world offeror and offeree are much more common...
Also - don't get too caught up on questions of fact such as the reliability of a third party... It will be enough for you to raise the issue, discuss the relevant case law and say that it is, at the end of the day, a question to be answered in court. If you want to, come down on one side, but the questions of law are where you'll need to focus your efforts.
Remember - questions of fact are usually never in doubt, and the deepest analysis you will have to offer is whether the facts fall into a legal framework. In this case they do, but the framework is simple and uncomplicated, even if it is a little underdeveloped.