I'm not familiar with any of Massie's other work and I picked this up to read when illness required me to do nothing. Otherwise I shouldn't have persevered.
I'd say that, as a novel, it's no better than a second draft. Some episodes are far longer than their content warrants, and longer than other episodes of similar weight (or triviality). There is much that is irritatingly superfluous - if a writer is admitting on the page that such and such is a digression, what's the point of leaving it there? Much of the book reveals assiduous research and probably a genuine love of the history but the many digressions appear to me as false starts in the plotting and they ought to have been cut before publication. The characterisation is shallow and the erotic stuff gratuitous, especially the homo-erotic, which seems to me as self-indulgent private fantasizing and, again, should have been rigorously checked for plot relevance before publication.
That's all if it's a novel. But I suspect it's really intended to be a film proposal. As such, all its literary shortcomings find a ready explanation, and it's revealing that the style becomes sloppier towards the end -- if the film-makers have read that far they won't be put off by the lack of copy-editing. I find it insulting that an author has foisted on the reading public a piece of work that is nowhere near polished enough to be a novel but (I suggest) is flying a kite at our expense in the hope that some film company will notice it. I'm wondering which part Mr. Massie has in mind for Kiera.
The anti-clerical analysis was fun but it wouldn't be enough to get me even to open the covers of another Alan Massie, far less to buy one.