Sure,... you can get the UK ambassador removed,... now that you know he was critical of you and your WH administration.
... but that doesn't change the facts.
The reality is the UK ambassador got caught. All the other diplomats that have reported on Trump's ineptitude are still around.
And any replacements will feel the same.
Killing the messenger doesn't change the message.
You can punish them for their words, but it won't change their thoughts.
The world still thinks you're an idiot.
"Ask members of the Washington diplomatic corps about the cables that Sir Kim Darroch, the British ambassador who resigned Wednesday, wrote to London describing the dysfunction and chaos of the Trump administration, and their response is uniform: 'We wrote the same stuff'."
"It could have been any of us,' one ambassador, who is still serving and therefore spoke on the condition of anonymity, said on Wednesday."
https://www.nytimes.com/2019/07/10/world/europe/kim-darroch-trump.html
This is the sad state of out nation in the eyes of world.
Respect is earned, it can't be demanded.