My issues with this book can really be boiled down to this:
1. Too many characters, resulting in zero investment, and a distinct lack of emotional engagement and punk
2. The hook in the blurb (the list) actually turning out to be pretty irrelevant to the story
3. Lazy, sloppy writing and plotting
This sounds a little scathing, so I'll elaborate below and explain a little, and I will also say that these comments are a reflection on the book only and not necessarily the author (I have read another book by Keris Stainton which I quite enjoyed, and was much better executed, which shows she can plot, characterise and write).
So, point one: MHGB stars five main characters, and much as I like books with ensemble casts, this shifting focus meant I never invested in any of the characters, and, because the book covers several months, often things I thought were going to happen and be interesting and dramatic ended up being glossed over, and therefore falling flat. An example: Lou reporting jealous ex Kyle for harrassment. This was a potentially interesting and relevant plotline, but we see so little of it, and we don't get to engage with Lou's feelings of horror and fear and shame because they are covered in about half a page! Her decision to report Kyle should feel brave and momentous, with the reader rooting for her, but we don't get to see her doing it, don't see or hear about Kyle's reaction, and don't really see how Lou feels afterwards. All the juicy scenes - the ones that are interesting to a reader - are omitted. It is such lazy writing to tell rather than show. What, therefore, was the point of that plotline? What did it add? I don't even know if this experience changed Lou as a character, or whether she learned anything from it, because I never felt I knew Lou in the first place. Lou herself could in fact be quite easily removed from the book and it would be better for it, because that might mean we got more pages to flesh out the other characters a little. They all come across as so empty and sketchy, and not like real people.
Other plotlines that were mentioned briefly and never came to much, or, in fact, anything: Liane's feelings about her parents, her dead friend Zack, Issey's family (why introduce them at all?), Dylan (what was the point of him, apart from the quite fun scene where he meets the girls?), Ella's stepfather's death (we don't meet him and we don't care about him and it seems to have so little impact on Ella...).
I got the feeling I was meant to invest in Ella's romance with Nick (which, on a positive note, is good to have in contrast as the book that focuses almost entirely on casual hook ups, which it presents as the norm - something else I'm not sure about, as plenty of 19 year olds don't have huge numbers of sexual partners, if at all) - but, again, we see so little of Nick that this never comes alive. The relationship between Issey and Liane felt slightly better done, and I felt like the book probably ought to have been about them. Paige had the potential to be interesting, but her role in the book went nowhere.
My second issue is the Fuck It List. It sounds like a fun hook on the blurb. It could create lots of fun plotlines. But it doesn't become part of the story until about a fifth of the way in (the first fifth instead is full of boring details about the house share). We never get much info about the guys/girls the girls "tick off". It feels wasted, somehow, just another thing I know next to nothing about despite having read the book.
Three, the writing is ultra simple, which combined with a dull plot in which so little happened (instead we get details about street names which mean nothing to anyone who doesn't know Liverpool, scenes with the girls' families who we never see again, details about what they eat for dinner) makes the book underdeliver. It reads like an unedited first draft in place. And I've already mentioned the show don't tell, which happens quite a lot, mostly because of the five POVs and the months passing.
I liked the premise of MHGB. I wanted to like it. But I had zero emotional engagement to this one and felt it was so poorly put together. My opinion only, of course!