Arthur - thank you - You've pointed me in the correct direction and I believe this is solved.
If this is useful to anyone else, here is the commands as implemented on each of the three EdgeRouters:
R1
Configure interface addresses set interfaces ethernet eth3 address 10.10.0.2/30 set interfaces ethernet eth3 description "MPLS" Configure GRE Tunnel set interfaces tunnel tun0 encapsulation gre set interfaces tunnel tun0 local-ip 10.10.0.2 set interfaces tunnel tun0 remote-ip 10.10.2.2 set interfaces tunnel tun0 address 10.11.0.2/24 set interfaces tunnel tun1 encapsulation gre set interfaces tunnel tun1 local-ip 10.10.0.2 set interfaces tunnel tun1 remote-ip 10.10.1.2 set interfaces tunnel tun1 address 10.12.0.2/24 Enable label switching and LDP set protocols mpls interface eth3 label-switching set protocols mpls interface tun0 label-switching set protocols mpls interface tun1 label-switching set protocols ldp router-id 10.11.0.2 set protocols ldp transport-address ipv4 10.11.0.2 set protocols ldp interface tun0 enable ipv4 set protocols ldp interface tun1 enable ipv4 set protocols ldp targeted-peer ipv4 10.11.0.3 set protocols ldp targeted-peer ipv4 10.12.0.3 Set up OSPF set protocols ospf parameters router-id 10.11.0.2 set protocols ospf area 0 network 10.11.0.0/24 set protocols ospf area 0 network 10.13.238.0/24
R2
Configure interface addresses set interfaces ethernet eth3 address 10.10.2.2/30 set interfaces ethernet eth3 description "MPLS" Set GRE Tunnel set interfaces tunnel tun0 encapsulation gre set interfaces tunnel tun0 local-ip 10.10.2.2 set interfaces tunnel tun0 remote-ip 10.10.0.2 set interfaces tunnel tun0 address 10.11.0.3/24 Enable label switching and LDP set protocols mpls interface eth3 label-switching set protocols mpls interface tun0 label-switching set protocols ldp router-id 10.11.0.3 set protocols ldp transport-address ipv4 10.11.0.3 set protocols ldp interface tun0 enable ipv4 set protocols ldp targeted-peer ipv4 10.11.0.2 Set up OSPF set protocols ospf parameters router-id 10.11.0.2 set protocols ospf area 0 network 10.11.0.0/24 set protocols ospf area 0 network 10.13.240.0/24
R3
Configure interface addresses set interfaces ethernet eth2 address 10.10.1.2/30 set interfaces ethernet eth2 description "MPLS" Configure GRE Tunnel set interfaces tunnel tun1 encapsulation gre set interfaces tunnel tun1 local-ip 10.10.1.2 set interfaces tunnel tun1 remote-ip 10.10.0.2 set interfaces tunnel tun1 address 10.12.0.3/24 Enable label switching and LDP set protocols mpls interface eth2 label-switching set protocols mpls interface tun1 label-switching set protocols ldp router-id 10.12.0.3 set protocols ldp transport-address ipv4 10.12.0.3 set protocols ldp interface tun0 enable ipv4 set protocols ldp targeted-peer ipv4 10.12.0.2 Set up OSPF set protocols ospf parameters router-id 10.12.0.2 set protocols ospf area 0 network 10.12.0.0/24 set protocols ospf area 0 network 10.13.239.0/24