Bear in mind MANN are aftermarket. Mahle Knecht is the OEM brand.
ECP or CarParts4Less are fine, although not particularly generous with the discounts at the moment. They used to be peram-sale like DFS sofas.
There's AutoDoc if you don't mind waiting 7-10 days (on average) for the parts to arrive, but they're well packaged and well priced. They're a huge warehouse in Berlin, so have access to all of the good stuff we can't get here.
Yes lots of repackaging and fakery going on.
OE suppliers are:
Mahle Knecht
Lemforder
TRW
Sachs
LUK
VDO/Continental
Bosch
ATE
Textar
et al
Stuff like 'Stark', 'BorseHung', 'TopRan', 'Febi' etc is all aftermarket tat.