Exactly, that is why all of your efforts should be geared to setting up a trust to run the chapel, not expect MOD to fund it ad infinitum.
In British culture; it is the 'family' who purchase the gravestone and maintain the grave until such time as nobody cares anymore. Clearly a lot of people are not prepared to forget the events of WWII, and nor should they be expected to.
The 'family' on this occasion are the Government whose predessesors declared war.