Found a Uniqlo shop that actually stocks Federwear (Oxford Street, London, U.K.) : r/tennis
25.06.2012. The Wimbledon Tennis Championships 2012 held at The All England Lawn Tennis and Croquet Club, London, England, UK. Around the grounds - General view. Wimbledon gift shop Stock Photo - Alamy
Wimbledon tennis shop hi-res stock photography and images - Alamy