I raised this point with several closer to the RPSI action in the past, and have been told over the years that the reason it was maroon was in case it was ever needed with any heritage stock. But it isn't, and the likelihood that it ever will is almost nil.
But this ghastly colour (sorry, DJ!!) isn't even maroon, or anything near it! Plain blue would possibly be best, though I do not want to open up a debate about what way to paint a vehicle whose entire life in its current guise was black'n'tan.....