Assuming the DVDs you purchased recently are those produced by BFS
Entertainment, they only contain the first eight episodes from series
The complete eight series have never been released on video or DVD
The first two series are available in England, though cuts have been
made to these.
In addition, series three has recently been released on DVD in the
We can only hope that the Dutch company will release further series
in the future.
A complete (and accurate) list of Onedin Line episodes can be found
in the Files section of this group.
Hope this helps.