As I was ordering various stuff from JSR anyway I decided, as a bit of fun, to order their cheapest red dot sight. That was the Gun Tuff ABS Red Dot Point Sight, for the princely sum of £8.99. Here's what the blurb says about it:

GunTuff ABS Red Dot Sight With 11mm Built In Mount
Simple Red dot sight for rifles and pistols with easy to use finger adjustments for zeroing.

Features / Specifications:
Built in 11mm dovetail mounts for most airguns / rimfire rifles.
Fully windage and elevation adjustable - just like zeroing a scope.
Straight through design (no magnification).
Unlimited eye relief - suits both pistol and rifle shooting.
Weight 80g, overall length 115mm, 11mm mount section length 50mm.
Battery (supplied) CR2032.
Supplied with instructions.

On receiving it I stuck it on my ancient Relum Tornado:
http://www.pbase.com/niblue/image/14...2/original.jpg
http://www.pbase.com/niblue/image/14...0/original.jpg

It has adjusters for windage and elevation - although not the best they do work and here's a 10 shot group I shot (at a little under 10 yards) once they were sighted in (more or less!):
http://www.pbase.com/niblue/image/14...1/original.jpg

That's about as good as I can do so far as I find it difficult to be precise with the placing of the red dot on the centre of the target. Fun and fast to use though, and my son particularily enjoys using it (makes him feel like he's in Modern Warfare 3 I think). I don't have a pistol that I can fit it to at the moment but hope to rectify that soon.

In summary - not a serious bit of kit for good fun for £8.99!