Nice! Good find on that P/N for the crank bolt, that's one we will have to save. Looks like you could even just buy a new one for pretty cheap as long as you were willing to wait for shipping from UK or elsewhere overseas. I see now that it crosses over to Febi/Bilstein 17230 which seems widely available, used on various other gas and diesel VW/Audi engines, I suppose that's no surprise.
I wrote a detailed reply about the idler puller but didn't submit quick enough and it didn't post.
I'll fill in more info later but for now I'll just leave this link...... this tool or anything similar to it is the answer.
https://www.amazon.com/Adjustable-Be.../dp/B089M99K71
Note that this particular design's adjustable width arms are the key to success. The one I have as a subsitute for Volvo 9995202 is exactly like this one that I linked here but it came from Harbor Freight years ago. However HF appears to no longer sell this style puller and the revised style puller they carry instead now (and commonly seen elsewhere) is a fixed-width design that probably would not work since the arms might not be wide enough to clear the OD of the idler pulley. So stick with one that looks like the Amazon listing above, avoid those that have a fixed U-shaped frame.
To do the job, you remove the inner "puller" parts from this puller and then use the outer frame in combination with a correct size/length metric bolt from the hardware store and some stacked washers to replicate the design of the 5202 puller. As you screw the bolt into the threaded inside of the idler pulley, it pulls the idler out of the engine like 5202 does. As a bonus if you keep the rest of the puller parts you removed in your toolbox, you also get a free universal pilot bearing puller out of the deal. Always nice to have tools that have multiple uses.