“I thought it was MI5 and MI6 holding him back per personally asking him not to declassify everything”
I cannot imagine why they would do that except for one reason. British intel was assisting in an effort to meddle in the 2016 election. And they weren’t just unwitting. They knew what the CIA was doing, and Theresa May was working against Trump.
This was a CIA regime change operation, this time conducted against the American government.
This was in my sketchy memory vault from September
https://dailycaller.com/2018/09/23/british-trump-declassify-russia/