Hannigan resigned a few day after Trumps inauguration https://www.theguardian.com/uk-news/2017/jan/23/gchq-chief-robert-hannigan-quits

He has since been implicated in a scandal covering for a paedophile priest.

https://www.theguardian.com/uk-news/2019/feb/24/ex-gchq-head-robert-hannigan-quit-paedophile-priest-edmund-higgins-reference

Also of note Charles Farr Chairman of the Joint Intelligence Committee and Head of the Joint Intelligence Organisation has recently died after a sudden illness this got very little press in the UK, a few obituaries that's it. It was actually the Gov. Uk website that announced his death. He was a heavy weight spook I believe he's had a few mentions on here.

https://www.gov.uk/government/people/charles-farr