Why do you have books that are fom uncompleted series? I mean you have Jane Casey's The reckoning The last gril The kill and After the fire, but not The burning, The stranger you know or Left for dead. Then there's Karen Rose's series, which are not all in here. Why?
I cannot answer for Jane Casey case especially, but in general there are at least three reasons, why a library collection does not necessary have all the books from a series.
1. The series has been complete, but during the years copies have been lost or stolen and new copies have not been purchased.
2. If the missing ones are the newest in the series, they are probably not yet in the collection but will be there later. The customer may always ask for the situation.
3. In some cases the staff does not know, if a book is part of a series or some parts of the series are already out of print, when the library would like to buy them.
The customers of HelMet libraries can always make an acquisition request. The library is just happy if the customers report about missing parts or in general about titles needes and wanted. So please use this possibility, if you think the collection is not gtood enough.