Righty, so thats the flow control thingy then, thanks.
Having unscrewed the lower part of the tap there is no insert, so do I need one? The very end of the removable part has an external thread which made me think that was where a sparkler fitted, now I think I might have a Dalex tap with some random spout, same size thread as on my Alumasc tap and the spout off that fits.
So, I need to get either something to go on that external thread or an insert?