They run in grooves and on top of each sash there are 2 recesses which you put a finger in and slide inward which releases the top of the sash. So now i am able to rotate the sash inwards and get better access to the bottom retention mechanism.
There apear to be nylon bushes which slide within the groove and are attached to spiral balances spirings, these have a metal pin which then sits within a groove in the bottom of the window. Question is how do I remove theses pins ?
I thought maybe they slide inwards towards the centre of the window but they dont seem to want to budge (maybe rusted in) before i force them really hard and potentially break something can anyone confirm how they should be removed?
(i know i still need to remove the screw on one side btw - its rusted/stubborn and even a impact driver wont free it!)