Basically, it works this way.
If you have several programs that belong to a series, and are grouped under one series name in MC, then you manually look up TheTVDB info for any one of the episodes in that series using the right click "Get Movie & TV Info" function, select the correct info from the possible options returned, then click "Use this data", MC gets the "TheTVDB Series ID" for the program, and saves it to all episodes for that series that you already have, in the "TheTVDB Series ID" tag. Then when you look up a new episode that belongs to that series, MC will look up the "TheTVDB Series ID" from the tag for the series, and use it to look up TheTVDB, instead of using the series name in MC.
You see, there can only be one "TheTVDB Series ID" value for a series in MC. You fill in a value for one episode, and all episodes get updated with the same value, at the same time.
TheTVDB Series ID for The Flash (2014) is 279121. Even though TheTVDB names the series "The Flash (2014)", in my MC library it is just called "The Flash", because that is what I want to call it, and that is what was used in my EPG data. So when I recorded a program called "The Flash" in the EPG Guide from OTA TV, it was correctly matched to the series I have called "The Flash" in the MC database, and MC looked up TheTVDB using the series number 279121 for new episodes after the first was correctly selected manually. Therefore it always got the correct data.
If you use "The Flash S01E02" in the first "Get Movie & TV Info" lookup for an episode, and select the correct program from the list that is returned, then all existing and future episodes will get the correct series ID. So once you have done the one manual lookup successfully, then do all the lookup for all the remaining episode you have in one group. MC will find the correct program information. Note that instead of doing one manual lookup, you could just enter TheTVDB Series ID for "The Flash (2014)" of 279121 into the appropriate tag for one episode, and the tag will be updated for all episodes. Then you can look up all the rest in bulk.
Simple huh?!
Well, maybe I could have written all that more concisely. Take a read of these threads if the above is confusing:
http://yabb.jriver.com/interact/index.php?topic=94870.msg653750#msg653750http://yabb.jriver.com/interact/index.php?topic=92703.msg640135#msg640135PS: If you just can't get the "Get Movie & TV Info" lookup to show the correct program, and you want to see how it works, first delete any value in the "TheTVDB Series ID" tag for one of the episodes, which will delete it for all episodes in the series, as shown in MC. Then the "Get Movie & TV Info" lookup will use the Series Name instead of trying to use any existing value in the "TheTVDB Series ID" tag.