I have written to my MP (Tory) to this effect: that we need skilled mediators and negotiators handling this from across the parties and not TM, who we know is poor at interpersonal skills and has poor judgement. (She had to be told to go out and make another speech that acknowledged that the object of the GE was not achieved and she is sorry about those MPs who have lost their jobs - she had to be TOLD that this was appropriate!)
Just because the British people voted (by a tiny margin) for Brexit, it does not mean that they voted for a particular style of Brexit or for only one party or point of view to be involved in the negotiations.
A true negotiator would not strive to be "bloody difficult" but would do what good negotiators do: try to understand the other "side". People will listen to you if they know you have listened to them. The EU is very very worried about Brexit because it knows that there are other countries queuing up to go and they are waiting to see how we fare. The temptation for the EU to give us a bloody nose to deter others is ever-present and being stroppy with them in the negotiations could be a disaster.