It seems that the Prince's Foundation would like to run a design review programme. Presumably this would be a sort of revival of the 'licence to crenellate', which applied a while back.
Prince Charles' tastes over the years have seemed to favour the classical rather than the Gothic, but it's never been clear whether he would really prefer to turn the clock back to roughly the eighteenth century - the peak of Georgian excellence, but by which time the powers of kings were already a bit restricted - or roughly the thirteenth century - Gothic architecture, but proper kings.
However, it seems that the popular view of the licence to crenellate - that it was a favour which was in the royal gift - is mistaken. According to the historian Charles Coulson, there was in practice not much restriction on building castles, and there was 'very slight chance of interference by royal officials even in so intensively governed a realm as England.'
But that was then.