I'll answer my own problem for the benefit of others. I have shown a mate, who is in the upvc window business, my bathroom window. The Espag. mechanism is completely cream crackered, the handle just will not open release the window.
His advice, and if you choose to follow it, I take no responsibility, is :
Remove the internal black wedge gasket, carefully from indoor / inside part of the window. This will release the external window lugs (like a plastic bezel that runs around the external part of the window.
This should allow you to carefully remove the outer glass pane. Then I'm told this will give enough play to allow a small crow bar to lever the window up and a thin filler knife to slide the mushroom headed locking screw to the open position and away from the "Mila" recepticle. Then you need to fit another Espag. mechanism.
I'll let you know how it goes - just waiting for the new mechanism.
Al, June 2009
