I think what Jacob is trying to say is that he's already re-done his SD with one of the villiers supplied coils at circa £100.
That's a lot of dosh to spend on a coil, let alone any of the sundry parts inside the points box.
I'm reaching the same point myself with my own SD. It's also lacking any spark, but i'm certainly not going to spend a kings ransom for an original villiers coil, not at that price anyway. I know i know, it's the price we sometimes have to pay to enjoy our little hobby with little or no guarantee that this will fix the problem, but even so it's still an awful lot of money nevertheless. (now you can see why so many of these old gulls end up for sale these days)
I fully understand that the issue with all of the villiers coils is becoming more and more of a problem to most of us now.
Some individuals have taken a more practical approach to the problem by whatever means is available to them. We've seen this before with some "modifications" to the smaller coils that are readily available from most places. Getting an old gull going again is an achievement in it's own right, and hats off to anyone that has the skills to retro fit parts from other gulls just to keep another worthy seagull going for the next few years.
I shall sit and wait patiently for someone to rewind my duff coil at a reasonable price. No rush
Jon