In many countries, members of parliament are elected on the title of political parties. For example, in The Netherlands, 81 parties have registered for the Dutch General Election, 2017. In most of those parties, the political programme and electoral lists are — at least in theory — democratically decided by the members. One of those parties (Party for Freedom, currently polling as the largest party at 21% of the vote), only has a single member (Geert Wilders). The party itself is effectively a dictatorship (but literally speaking, also a perfect democracy).
I have read a proposal (not supported by Mr. Wilders) to require parties that wish to participate in the elections to be democratically organised and member-based, arguing that it would make democracy less vulnerable (the wannabe-dictator could then be ousted by his own party members even if he has a majority in parliament). Regardless of whether or not such a requirement would actually help, my question is:
Are there any parliamentary systems where such a requirement for political parties exists, to accept members and be democratically organised?