(Reviewed after watching the first two episodes of season 1.)
The basic problem here is that Domino Day is not a sympathetic character. If, as the stated "storyline" suggests, "she is haunted by her need to feed on the energy of others", she should really be actively struggling with her need to feed. Instead, she seems to succumb quite easily to it. It all feels a bit "it's not my fault I'm doing bad", rather than "I will overcome my addiction".
The second problem is that the story and "world building" are rather thin. The "magic shop" seems more like a joke shop, not least because the shopkeeper is so weak. Surely he should have some strong magic to call on? And while this is, supposedly, set in Manchester (England), nothing we see seems in any way uniquely Mancunian.
The third problem is that this feels very tame. Perhaps there can't be any actual sexual content because the commissioners (the BBC) are looking to export this to markets where a stronger offering would not be acceptable? Who knows. (And these three problems are certainly not a charm.)
If you've the urge to watch an interesting/adult magical drama, try The Magicians (2015-2020).