The amount of foam isn't relevant, it's the look from outside. The window externally looks fine, it's just that it could've been a tad wider, but that is being fussy.the windows might have been mismeasured due to the amount of foam
Internally it's a dogs dinner, both windowboard and architraves are wrong.
The biggest mistake of the whole job is poor communication at the beginning. The fitter should have talked through the problems and the options.
You should hold back some money so you can redo the internal trims, but you can't hold back loads as you do have windows and the fitting