Don't let it bother you. Those are rookie numbers. I regularly end up with boxes full of unopened oem spare parts, and justify keeping them "just in case".I have a feeling the slave cylinder was at fault here as there seems to be more meat on the old plates than the new ones. I think my "friend" who pumped my clutch maybe 100 times pushed the slave cylinder piston out too much and it wouldn't retract fully, because I was also complaining about my lever coming back to the bar too far to, this would make sense, so maybe nothing wrong with my old oil or clutch in the first place and I have just spend £570 for nothing. Mind you, it won't need to be done again for a while.
The lesson I have learned here is always check the cheapest thing first, the slave cylinder, but to be honest, I didn't really know what a slave cylinder was until this saga started lol so it's all a learning process that we all have to go through.