The short answer to this is that they would not be trained to any other than the most basic level. On delivery they would be shown a PDA and how to scan something (which anyone can do) and then be sent on their way. It has been known for agency staff to go straight home after realising that they would have to work outdoors, that is how unprepared they are for the job.
In short, Royal Mail as a company do not care about the level of "service" that they are currently providing. They are trying to point the blame at the workforce when in reality they are causing most of the problems, and this is a good indication of how things will be if they do everything they want.
I left Royal Mail a few months ago, I have no reason to take sides on this other than how my own experience and knowing how things should work if the company wanted them to work.
Adding that there is a report today that RM have £1.7Bn available to defeat the CWU. That money will more than cover compensation payments and the like, they really do not care what happens to any item in the system.