If your gap is 1mm leave it alone.
You didn't really change anything between it not starting, then starting - other than disconnect/reconnect the CPS - it's possible you have a problem with that connector/harness but it could be just coincidence. Or maybe you cleared some metallic crud off the sensor when you checked the gap?
- Clutch is not an interlock for bike to fire off and run - ONLY for the starter to run; since starter is running, clutch switch is not an issue
If Neutral switch is made then side-stand is not a factor either (since OP tried with both in Neutral AND side-stand up at same time, it is unlikely this is an issue as would require BOTH to be failed which is realistically beyond likelihood)
If you can't find ground block
you may not have one - early T595's appear to use a different harness ground scheme (although have never seen one personally)
It should be in the area in front right side of the battery box - if not obvious you probably don't have it.
You started off calling it a 'cold start' problem - then in text, described it more as problem restarting after it was laid up.
Is it always more difficult to start when it's cold? And OK when it's been warmed up?
You can make a change in the Map that can enrich the fuel ratio for cold starting (it already does, maybe needs a bit more)