If a Queen’s Guard was provoked and pointed their gun towards the person provoking them, would they be arrested and removed as a guard?

Simple answer no they would not be removed as a guard , as long as no action was taken outside the camp , 

a soldier on guard duty can use Minimum Force necessary , to deal with situation as long as with in the boundaries of the camp

In this case the camp would be the royal palace which ever one

Any action taken outside The camp would mean immediately arrested by either military or civilian police

How ever the armed police on duty can use any force any where

Normally the guys with side pistols there legs and the machine guns fully loaded will step in

They are the royal protection squad and diplomatic police

If a guard is being harassed they will step in, if they think a criminal offence is taken place

How ever being in the army we have two documents to carry at all times

1. armed forces I’d warrant card
2. Fire arms licence
3. We are licence to carry fire arms on or off base it duty
4. AS a member of the army you are never off duty
5. Members of the Royal Air Force are not licence to carry firearms
6. The RAF regiment should be same as army , I am sure a member of the regiment will answer that , serving or retired
7. Is actually very rare for members of the army to carry firearms while off duty
8. Well we are not ever off duty , so I will say while not on shift

You have to remember the queens guard are very highly trained and unless a life was in danger , they would not react

We are trained to stand to attention for hours , till told to stand at ease then 2nd command stand easy

When you hear the guard told to stand easy you best start running

The police would step in well before the guard reacted

Remember the guard also has hundreds of mates as back up , hiding in the guard house ready to react or billet block

Remember a queens guard has the full backing of his regiment and the royal protection squad and diplomatic police

And then the full back up of the security services and the metropolitan police

Remember the police are there to prevent a breech of the piece as well as protect the royal palace

What you also have to be aware of every inch of the royal palace is being recorded by cctv cameras which have controllers watching the screens 24 hours a day

I would worry more about the police on duty then the queens guard