Just how accurate is the portrayal of Thatcher and the Queen's relationship on 'The Crown'?

So, you've watched the new season of The Crown. 

You probably have a few questions, right? Like, did the Queen and Margaret Thatcher really have such a terrible relationship? Could you really cut the tension between Buckingham Palace and 10 Downing Street with a knife? 

If you've binge-watched your way through a big chunk...