I am hoping to change the vertical window section of this Keylite window for a longer aluminium framed window that will reach down to just above the radiator. Any help or guidance would be appreciated particularly how best to separate the two sections. The vertical frame has a V shaped top rail into which a roof batten is laid and the roof section has two metal brackets that are screwed to this batten, I think. I realise I will need support the roof window during these modification. Thanks
