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Without access to a Sashmate, removing the glass could be a sensible idea if it's internally glazed.
https://glazesafe.com/sashmate-user-images/If there's a window cill just below, you can often slacken the bottom hinge screws sufficiently to allow the hinge track to pivot around them. Remove the upper screws and allow the top of the sash/hinges to go outwards and guide the bottom of the sash to rest onto the cill.
Undo the two remaining screws and bring the sash inside.
Cheers and @nathwilson22
It's top hung and probably not too far off a SqM so seems pretty awkward to do from the inside I'd have thought.
My thought was one person up a ladder holding it and another on the inside doing the screwing/unscrewing. I can't really picture how there would be space for one person to hold it and another to fix it from the inside.