The lower profile ignition module arrived today. I've fitted it in the spare spare distributor and it just goes under the 44D rotor arm. But it would need the flash guard modifying to make it fit and I ain't doing that.
Oddly the unit supplied is clearly not for a 25D: The grommet is all wrong and wouldn't even fit a 45D with the female spade on the black lead. The rotor arm seems to be a 45D one - too long in the arm for the 25D and 44D. It also sits 2-3mm higher, but I think that's largely because it's a piece of crap as the red 25D arm and the red 45D arm I shortened the brass on both fit fine. But I reckon I can make the module fit the 25D for drilling out an old grommet.
As it won't take the flash guard, even if it will drive the 6v coll (waiting till the end of the Lancashire rainy season to check) I think I'll still get one of the Sparkrite SX6000s in the next credit card month, which SimonBBC's measurements say should fit properly.
Graham