looking for some quick assistance here please (probably from @Nickfromwales as the resident hep20 expert!).   bought some 15mm -> 10mm spigots for my HRC pipes. they look like this:     I can't fit an insert in the end that goes into the 15mm connector on the manifold. I presume that's by design? I just need a 10mm insert in the 10mm pipe that goes into the 'mushroom' end of the spigot?   I've found some pictures on the web that show these spigots with