Pretty much all of fares sold directly by BA - from the very cheapest discount economy fares to the more flexible first class fares - are published and readily accessible through tools like ExpertFlyer.

You will want to be careful about referring simply to "full fare economy", which has the potential to be ambiguous. Also, if allowing people to upgrade by themselves if they choose is one of the things you're thinking about, you will probably want to bear in mind that some business class fares can be cheaper than the most expensive economy fares on the same route. You may want to think about whether you want them to be able to claim more cash than they actually spend on the ticket. And what would be your view about them choosing a "no changes, no refunds" ticket if there's any chance that you may have to change their travel plans when you're paying for their travel?