Shower screen blocks are the only parts listed as suiting Regency™ screens: a pick-up block in black, the same block in white, and a set of three sill blocks in black. All three are also listed as replacing Ideal™, Showerite™, Norfe™ and BGC® blocks, so one moulding covers a number of older framed screens. A range made up entirely of blocks tells you where the trouble is. The pick-up block that carries the sliding panel goes brittle with age and cracks, and the sill blocks underneath wear flat, which lets the panel drop and catch. Remove the old block first and match its shape, peg positions and fixing spacing against the photographs, and note the colour — black and white are the same part in two finishes.