I've just bought a 15w soldering iron from Maplins. Turned it on and it glows cherry red. Is that normal because my 30w one doesn't do that.

No, it shouldn't get that hot.

I bought one of those recently and it din't glow red hot. It did have a mind of its own though! I plugged it in and waited about 10mins and nothing, stone cold.
20mins and nothing.

I dug the box back out of the bin along with the receipt, unplugged it and burnt myself on the swine!

Started using it and it worked for about 10mins then shutdown right in the middle of fixing a joint!

Some soldering irons will shutdown if not used for a length of time (like a screensaver) but I was actually using the damn thing!

It works intermittently now, I just have to wait til I see a bit of smoke from the tip and crack on until it decides to go to sleep on me, then keep poking bits of solder at it until it melts it again.

Piece of junk!

Cheers mate, it was my mistake it doesn't glow with a bit on!

LOL