There are two camps who think that this is either a fair or unfair puzzle. I'm sat on the fence as I believe it is borderline both. This is why :-
Fair
1. very tough but, although extremely challenging, doable
2. grouping of the circled cells is very helpful and both negates a lot of grid staring at the end and assists in solving the unclued 9a.
3. The double clues do assist getting a foothold on the grid, especially at 5d. Notwithstanding that, the one at 4 produced a massive red herring for me.
Unfair
1. Far too much cold solving required, for me it was 100%!!
2. Too many unclued entries, especially how they are bunched
3. Clues nearly always indicate the number of words, but no indication at all for the other entries required.
4. 13a isn't the only entry not in my BRB. My entry at the top of column eight is a variant spelling one letter shorter than the entry in Chambers.
A masterful construction by Artix, whose future challenges will be met with a good deal of trepidation.