A quick search of various university sites seem to ask for between 1 and 2 years post reg experience. I think one year post reg is incredibly ambitious though.
IMO, the more experience you have the better before embarking on a course like this, as it helps to have a broad knowledge base gained through experience of encounering patients in your clinical area of practice to get through this course. The five years that you have already been told is reasonable.
It is worth also considering what direction you end up heading in career wise, the V300 is embedded as a module in quite a few post reg courses, in particular the advanced practice MSc for example. I also think prescribing in some format (may be the V100) is included in the DN specialist practitioner course. If you get into training posts for jobs like these, then the funds are usually covered.