Merwede posted the longer version for possible future orders. Other nations are looking for sea lift also, but wish to move a battalion group instead of a company group, thus the longer version of the Canterbury. The Swedes are looking for more of a joint task force ship, to move a battalion group, but also to act as a mother ship for her mine sweepers/hunters and smaller patrol craft.
The Australians are looking for a third sea lift logistics ship. There are other navies searching for sea lift too, with different needs and wants. Funds are tight all around the world, any multi-purpose ships that can do both tanking and sea lift may be marketable.
As noted, although not confirmed, even New Zealand is thinking in terms of a mixed used tanker and logistic ship to replace the Endeavour. While New Zealand may wish for a new tanker soon, a bit more sea lift wouldn't hurt. There are many designs out there because all of the shipyards wish to sell and build ships. Remember the Canterbury was ordered for 53.5 million Euros, about $100 million US$, and $186 million NZ$. The Endeavour ran close to $50 million NZ$ back during the late 1980s, therefore a multi-task tanker/sea lift would run more than the price of the Canterbury, but should still be under $250 million NZ$, or much less than 100 million Euros today.
As for the OPVs. I repeat it would be a large error to use these ships as frigates. They do not have any sonar, electronic counter countermeasures, surface to air missiles, surface to surface missiles, or even a proper three inch gunmount. They are totally unsuitable as a war ship. Just because they may look similar to a frigate to some does not mean they are. They were bought to be used as EEZ patrol ships. A $60 million patrol ship should not be considered a $400 million frigate, not by anyone or by any government.