Hi, well I also bought one of those £4.99 scribers, and although it wasn't very quick in arriving, it came today and was before the estimated delivery time. I haven't ever had one of these before, except one that I found several years ago, which was very rusted up and well abused, as the very tip was broken off, and the nut that holds it into the body wouldn't undo, although it would turn about one or two degrees. I had to use a bit of very brute force and ignorance with two pairs of pliers to get it off, which split the nut and busted the screwed part off the body that held the tip in place.

Needless to say the new one works OK.
Regards Nick.