I'm pretty sure I have finished this and have the right number of 'further cells' but I am not very satisfied with it. I am not sure about the wordplay for either 42 or 44 and the 'message' did not make any sense until I Googled it.
It also appears that we have to shade in a 'signature colour' for which I do not have a marker pen. Stationery shops are closed due to lockdown so I am not sure what I can do about this, apart from write a note saying 'Yellow is the new ****'