I came here via google, hence the thread fro, the dead, but I looked into this as part of my degree studies so thought I'd share a bit of what I learned for others!
Lidl powertools are generally made by Einhell (who usually subcontract to Positec - they make Worx, JCB power tools,
Screwfix own brands Erbauer and Titan, and many others - hence the interchangeably of batteries. Positec also own the Hoover, Vax, and Dirt Devil brands among others) or Grizzly, who seem to have a sideline in power tools in addition to their core garden tools. The Bosch assosciation seems to have come from the colour scheme, though I wouldn't be surprised if some old Bosch designs were involved or even if Bosch was the OEM on some lines. Incidentally, Einhell also own the Ozito own-brand used by Bunnings and Homebase, hence the uncanny resemblance of their tools!
Parts for parkside tools should be available from the places detailed in the back of the manual, though at these prices it's probably just worth throwing the tool in the bin and getting another. It's easier to justify buying a spare part (plus shipping) for a tool that cost £100's than one that cost £30. In Germany you can order Lidl power tools year-round online it would seem.
There is much branding and marketing at work in power tools. For instance, Ryobi (except in some markets such as Japan), AEG, and Milwaukee are all owned and manufacturered by TTI based in Hong Kong. Black and Decker, Stanley, and De Walt are all part of Stanley Black and Decker Inc. The latter have been known to use Positec themselves in the past though I have no idea if this is current practice (something tells me it isn't). Of course, the specifications various products are made to vary with the most durable components and innovative designs tending to be used in the pricier brands, but part of the reason for the low price is due to standardisation and bulk purchasing of parts.
Personally I have no issue with Parkside tools and often they are cheaper than the equivalent
Screwfix titan or erbauer branded item, but I wouldn't be using them if I was a contractor either. If you are looking for Hilti or even Makita durability then you will need to pay those brands prices! I will definitely be purchasing one of the parkside impact drivers next time they come in to store, though as they are made by grizzly (even says on the label) I'm not sure the battery will interchange with my Positec stuff.
There's an interesting couple of inforgraphics at this link (if I can post it) which demonstrate just how big some of these companies are (who ever heard of TTI or Fortive - look at their share)
http://pressurewashr.com/tool-industry-behemoths/
Of course, who makes what and in whose factories is anyone's guess, but the varying experiences of these off-brand (and even big brand tools such as dewalt) could be explained by the rather complex manufacturing relationships in the industry.
