Spitfire Spitfire starter ?'s

The last time I rebuilt the starter on my 75 Spitfire it went relatively easy. The inertia spring was retained by a threaded collar.
I am trying to rebush the starter on my 79 and the collar is held in place with a retaining clip and spring pressure. I have looked for inertia starter tools
to do this and can't seem to find any. All I can think of is to try two C clamps to compress the spring. Suggestions as to where I can find a tool to do this
or any other method that would work, would be great.

It has been a while since I removed an inertia starter spring. I believe what I did was take two pieces of 1/4" thick steel bar about 1-1/2" wide and cut slots into them to fit around the spring and appropriate part of the Bendix. I drilled and tapped one plate and added clearance holes to the other so I could use 5/16 or 3/8" bolts as drawbars to pull the plates together and compress the spring.

Sorry for the vagueness. It has been too many years to remember the details. See the link below for images similar to what I did. The tool I made was rectangular as opposed to the round profile shown in the link.
https://www.worthpoint.com/worthopedia/inertia-starter-motor-armature-spring-543355002
and
https://www.worthpoint.com/worthopedia/classic-car-starter-motor-bendix-514411900
and finally... how it looks in use
https://www.howacarworks.com/illustration/1133/changing-the-bendix-on-an-inertia-starter--2.png

Doug, Thank you, that looks like something I can make from the scrap metal I have kicking around.

So that is what that tool is. I have one sitting around the shop that I come across at times. Could not remember what it was for.

David