Freenet installer fails with "Can't check signature: public key not found"

[unclehook]

Trying to install a new Freenet container with latest release.
The install script fails with :

gpg: /freenet/.gnupg/trustdb.gpg: trustdb created
gpg: key 7AA9C2A3: public key "Florent Daigniere florent.daigniere@trustmatta.com" imported
gpg: key 7EDBA5E0: public key "Steve Dougherty (operhiem1 Release Signing Key) steve@asksteved.com" imported
gpg: key 1946AA94: public key "Matthew Toseland (2013-2018 key, higher key length) matthew@toselandcs.co.uk" imported
gpg: Total number processed: 3
gpg: imported: 3 (RSA: 3)
gpg: Signature made Sat 06 Jan 2018 09:16:51 PM UTC using RSA key ID FD6C57F9
gpg: Can't check signature: public key not found