I have just received this item, but will need to return it, as the reviews here are correct, and I already have the episodes.
I would just like to clarify something. There are two main types of box set for Midsomer Murders. There is a "collection" box set (10 investigations) and a "series" box set. The collection box set contains random episodes that are in the series box set, like a compilation. In order to avoid buying the same episodes over again, you'll need to stick with one type, either series or collection, as one of the reviewers here has previously stated.