Thanks everyone.
Yes these were all taken with the ASI071MC. There isn't too much light pollution well no more than any other target anyway.
I rejected anything that had a FWHM higher than 3.5.
Ill try stacking just the newer ones as suggested, its a bit of a shame to waste all that data but if its garbage data then I guess I was never going to be able to use it anyway.
This is a link to a flat contour plot (this is from a few nights ago though).
https://astrob.in/full/369818/0/
This one is my current master flat.
https://astrob.in/full/369820/0/
So what about integrating and calibrating each nights lights with their own calibration frames and then integrating the master lights together? Reckon that would work?