We've had the magnet for as long as I can remember but I haven't seen it for years until recently when I found it again whilst clearing my late mother's house. We had a bigger, slightly different one too but have lost that, and I couldn't remember if this was the one my dad said was used for sticking charges to metal vehicles. I'm pretty sure it is but wanted confirmation.
Unfortunately it's been in the shed and has gone slightly rusty! It's 2" wide across the poles and 1.5" high, made from half-inch thick iron and the gap between the poles is just over 1".
well they are exactly what I can see on these pics. Do you have the book East Ridings Secret Resistance by Alan Williamson. If you do then on page 22 there is a picture of two of them. If they are what you say then you have a great little piece of history there mate.