"converting" a utility cupboard

[domesticbadger]

In that case, have you considered reducing the height of the cupboard? You could have an external small door at ground level providing access to the gas meter, then inside you could have either a space or a separate cupboard from there to the ceiling. Of course how useful that is depends on what you want to use it for - and it doesn’t solve the issue of the electricity meter, which you would presumably have to move down or something.

I mention this because I once knew a house where the small gas meter cupboard was accessible from the porch, and inside the top of it was a handy bedside table!

There would need to be an internal access regardless, as the access to the gas meter would be too limited from an outside cupboard.