Made a discovery by chance. I mentioned earlier that even though I had restore set for 20% of my 250gig drive it only had 3 points and was only using around 45gig of space.
I deleted all the restore points and re-enabled it. It would have wanted 170gig for that same 20% setting. Weird, so I've now dialed it back to 10%. I'll wait and see now if more the 3 points accumulate.