Recently replacec my ancient side hung hinges.
Obtained stainless MILA hinges from Screwfix and replacement (slightly larger diameter than the original) stainless panheads from the bay.
Essentials for me was a pair of suction grip handles (£9 apx) to make handling the window units safer, and someone to pass me the screws during the initial securing of the top hinge - stainless screws do not stick to magnetic screwdrivers so needed to insert the screw by hand before I could use the screwdriver.
Some screw holes of the old hinges did not match the MILA replacements, solved by drilling new holes, clearance size in the hinge, smaller (apx 1/2 clearance) in the frame.
Tips;
Do not remove the window handles, they make an extra grip if needed.
Measure the old hinges twice before buying the replacements.
Expect the old screws to be of different lengths and drive bits.
Sucker marks can be difficult to remove, clean as soon as the sucker is removed.
Lastly remember the original windows were probably installed when UPVC was in its infancy, nobody was a highly skilled window maker or fitter. I found four different screw types, some screwed into fresh air, and worst of all the outer frame bent out of shape by over tightening of the screws, the cause of the draughts and a problem I have still to solve.
