If it is really a continuation with the same vehicles it could be on the same page (and an empty page for the other IMDb number, with a link to the main series)
Otherwise I guess it can be listed separately.
I wonder about the title though, it is strange that IMDb lists it as "Miniseries". It would be more logical to have it named "Superwog Miniseries", even if indeed the Youtube video are titled "Miniseries" alone (but they also include the channel name).