Has anybody found a decent make of toilet seat,the ones from usual DIY shops do not seem to fit securely,the securing spindles are half the diameter of the hole they have to go through,and the adjustment relies on one small screw in the hinge part,within a few days the seats work loose and slide about on the top of the bowl,the whole design principle seems flawed.
Google for Croydex Sit Tight seats. They have fittings that are bonded to the pan to stop slippage. I fitted one for my Mum, and it has stayed rigid, though the nice chrome effect fittings have corroded rather quickly.