Not quite sure what you are driving at. Can you be more specific.
For example....Do you want to raise 500k for a new charity, eg worlds largest tea party, or something longer term like a home for rehabilitating wounded or a homeless shelter. Or is it regeneration work?
What is a military community action plan? My relevance is that I am a Director of a community centre for regeneration in a deprived area. Our initial fundraising was 6mil for building works(local govt, NHS and SWRDA grants) on top of which we apply to various pots for grants for projects (sport for england, return to work etc).
Happy to help and may know one or two who can help more if I can understand your project a little more