You can't rely on anything being 'rebadged' brands. One batch may be as you say but the next batch something different.
You can probably rely on the Infiniti brand wherever you buy it from.I've always found their DVDs OK.
7dayshop is a good place to buy as they are post free as is Choice Stationery.
I've been using DVDs from Tesco recently and find them OK, so their CDs are probably alright as well.
Bear in mind that most CDs and DVDs are made in just a couple of factories in the Far East regardless of the brand.