Looks like I only lost the one mark for putting ribosomes (structure M) instead of nucleus. Also, not sure if it's been pointed out, but the test cross in 2a)ii is wrong.
Thanks to everyone that put this together. 
I think that they may well not award the mark for q1a structure M. The biology assessors have been known to do worse in the past (see: intact skin) and rarely acknowledge their own errors, no matter how obvious (see ethylene vs. ethene). So I wouldn't pin your hopes on getting that mark.
Silly Microsoft word put a capital letter in the Punnett Square and I worked off that! - sorry - will update those in a second.
I don't know where nuclear DNA is specific enough for 7aii to be honest.