Just found this on LH's UK site:
http://www.lufthansa.com/uk/en/Late-..._p=DE&blt_l=en
In general, Late night Check-in is possible for all flights operated by Lufthansa or one of the Lufthansa regional partners and is available at numerous airports.
The evening before your flight - but at the maximum 23 hours before departure - check in your baggage at a check-in counter or check-in machine and choose your seat. Then you receive your boarding pass. The next day you go directly to your departure gate.
Please note that you can only check in at the check-in counter with an Economy Class ticket in exceptional circumstances. Instead, please check in conveniently online, via your mobile phone or at a check-in machine at the airport.
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