There the parties are much more cohesive, the party apparatus determines who runs for the posts. There are no primaries like here.
And in a parliamentary system, the legislature and the executive are almost always of the same party (or coalition). What that means is that it is much easier for the party in power to ram through pretty much whatever it wants... which I’m not crazy about. You end up getting wilder swings in policies as different parties get into government.
Basically what it means is that there is no separation of power between the legislature and executive.
I like our system better - it is more stable in the long run.
Labour had a leadership primary and it didn’t work properly. Low turnout with only radicals showing up and electing Corbyn to be the party leader. He is very unpopular outside of the radical circles and that is why the landslide Tory victory.