If you're a Prime member and you have a Kindle device you can borrow one book per month absolutely free from the Kindle Owners' Lending Library - and the entire DI Skelgill series is available.
Here's a link with a short video that explains it all:
https://www.amazon.com/gp/help/custom...(If that doesn't work just type into your browser something like "Amazon Help - Borrow Books from the Kindle Owners' Lending Library".)
Basically, all you have to do is open your Kindle and click on the Kindle Store icon (the shopping cart, or trolley as Skelgill would say). Then you click on the drop-down menu (3 horizontal bars, top right), and from the list that appears select the Lending Library. Once you're in there, search for the title you would like, and on its product page there should be a button that says "Borrow for Free".
So - why not try searching "Skelgill" - it seems to do the trick! (Oh, and I'm sure other good detectives are available.)