Hi Glasso welcome to the forum I have attached the tech sheets for the miyota OS11 for your intrest, Follow jdm's advise and pick out what remains of the glass carefully look and see if it has a gasket sealing the glass if so be careful removing it. Once measured and you have the dimentions Cousins.uk watch parts will be able to supply or on ebay look for a seller "watchfan" he seems to have a comprehensive list.
Miyota 0S11 - Specification.pdf
Miyota 0S11 - Parts List.pdf
In my engineering days, anything fitted with loctite (screws etc), were given a sharp tap on the end before attempting to remove. This seemed to break-up the loctite and the screw could then be removed easily. Not sure how it wold work on a watch stem/crown. Perhaps giving the crown (stem-up) a good tap on a solid surface might do it, but not sure if enough force could be transmitted.