I'm not particularly worried about the base not being "typical" Monart, not on a surface decorated thing. These were far more variable than any of their other output, as said there, M.
And the glass has ended up being very finely blown towards the base in this particular piece, not that they didn't sometimes try to put a button on finely blown glass- but that does tend to give rise to annealling cracks.
Their facilities were rather primitive. They were experimenting and attempting to produce stuff that would be hard enough to make with modern facilities and current improved metal recipes.
The Ysarts were doing stuff way beyond their time - a forerunner of the Studio Glass Movement.