Instructions:Free £20/€20 off flight
I just booked a flight & Google'd Lufthansa code & found this £20 off promotion. Worked for me, might work twice if you do twice & book out & return portions separately but I don't know.
"The voucher can be redeemed between 07/07/2014 and 31/07/2014.
Travel must be between 07/07/2014 and 30/09/2014.
Vouchers are only valid for itineraries where all flights are operated by Lufthansa and Lufthansa Regional Partners (incl. Lufthansa City Line and Eurowings).
The voucher is only valid for flights departing in United Kingdom and can only be redeemed at www.lufthansa.com."
Email arrived instantly for me, check spam folder if not in inbox.