Cheers jmcilhinney, that's definitely put me a step in the right direction, and after tweaking my relationships in the dataset designer, I've got my three BindingSources connected to each other.

However, the resulting behaviour isn't quite what I was aiming for. The last BindingSource only shows data related to the selected record in the middle BindingSource, rather than all the records (which makes sense, because that's the desired behaviour between the first and middle BindingSources).

Can that be altered?

Or am I just better off building a view into my dataset that already does the join between two of the tables?