As far as I can tell, those series haven't been released in the UK on DVD yet. That's probably because an online service (such as Netflix) still holds the sole UK rights. So the only DVDs offered for sale are expensive imports (which might either be in a foreign language, such as Dutch, or require a region-free player to view them with).
The increasing popularity of streaming services (such as Netflix and Amazon Prime) means that DVDs of TV series are taking far longer to come onto the market than they used to and, indeed, it's possible that some might now never make it onto DVD.
So all you can do is wait and cross your fingers that there will actually be a UK DVD release of those series. Sorry!