Thanks for the (English) replies.
I can read/talk French to a satisfactory level but not write.
The router is new and has had no firewall rules added. The only active one I can see is the default NetBIOS block. Besides, the LTE is getting an address using DHCP so think that's OK.
I see the following in the syslog :
2019-01-19 13:36:49
WAN1 DHCP ==>XID = 0x7b92c829, Client IP = 0.0.0.0, Your IP = 0.0.0.0, Next server IP = 0.0.0.0, Relay agent IP = 0.0.0.0, Option:
If I force the line to ADSL2+, it takes a long time to connect and occasionally fails. If it does connect, WAN1 is shown as connected but without and IP address.
More info :
Votre offre :
Freebox dégroupé total (sur numéro inactif)
Identifiant technique de ligne ADSL : 0549XXXXXX
Raccordée actuellement en offre : Dégroupage total NDI
NRA : CIV86
Longueur : 1358 mètres
Affaiblissement : 20 dB
Adresse IP : 82.64.XXX.XXX (static IP)
Votre ligne permet de bénéficier des services de Télévision de la Freebox
Thanks again for the assistance.