Most of Lidl's German stuff is exactly what they sell masses of in Germany. The bratwursts, bockwurst, Nürnburger sausages are all excellent, as are the hams and cold cuts, and the breads and rolls. Don't forget to buy a jar or two of sauerkraut and German mustard for proper verisimilitude!
My neuro-psychologist, an expatriate German who has been over here for about 25 years, and who usually bought his German goods from a specialist shop in Knightsbridge (at Knightsbridge prices!), was a bit startled when I recommended he try Lidl and Aldi, but was very glad he listened to me (and his wife sent a "thank you" too!), as he was able to get much the same stuff for less than half the price,
and their beer and wine selections are better.