I'm an Australian citizen actually, not a British subject. I was naturalised decades ago.
And sorry, the BBC isn't a propaganda channel for the British government or the British monarchy. Many times it's quite the opposite and strongly criticises the Queen, the BRF and the government, as discussions on the forum about several unfavourable documentaries featuring members of the royal family in the past will testify.
As I said a while ago: The BBC is by far the best when it comes to royal documentaries/coverage, with the exception of the BBC two documentary Reinventing the Royals and maybe the Thames Diamond Jubilee Pageant (but that was because of the bad weather).
Their coverage of the Queen's 80th birthday celebrations, her Diamond Jubilee and her 90'th birthday selebrations (so far) has been very good and very pro royal.
And their documentaries: Elizabeth R: A Year in the Life of the Queen (1992), The Queen at 80 (2006), The Diamond Queen (2012) and Elizabeth At 90 – A Family Tribute were very good and very pro royal.
I liked Monarchy: The Royal Family at Work from 2007 as well (with the exception of the Annie Leibovitz thing)
Their coverage of the royal wedding in 2011 was criticized by royalists to be anti monarchy friendly ( something I disagree with) but the coverage of the actual wedding day was very pro royal.
The ITV is also very pro royal as we saw with their coverage of the Wedding, the Diamond Jubilee and the 90th birthday and their day to day coverage of the monarchy (if there are somthing to cover) is very pro royal.
Their documentaries: Elizabeth: Queen, Wife, Mother (2012), Our Queen (2013) and our Queen at Ninety (2016) was very pro royal.
And as a professor said (I think it was in the telegraph) both BBC and ITV are much more pro royal now than they were in the late 80s and throughout the 90s
Sky news and Channel 4 are much more anti royal, but they are very pro Queen.
Sky's coverage of the Wedding, the Diamond Jubilee and the 90th birthday was mor balanced with both monarchist and republicans in the studio, but their documentaries are very pro royal.
The same applies to channel 4's coverage, but their documentaries are not reliable and is characterized by gossip.