That link states that
"The letters suggest the decision to sack Mr Whitlam was made by Sir John, and seemingly him alone.
In his letter to the Queen on the day he dismissed the prime minister, Sir John said he made the serious and significant decision without tipping off the Sovereign first."
Which shows the UK Monarchy didn't dissolve the Whitlam Government , infact, the UK Monarchy weren't even told about it until after the event