Looks like a LsL top yoke these alone for the R1 make £100 s/h on evilbay.
Regarding fender extender early forks ie 4xv - 5jj use the 1st generation mudguard and no fender extender was ever made - 5pw forks share the same mudguard as the gen 2 so you can get a fender extender for that mudguard. Now my set up is the early forks and I was able to fit a fender extender perfect I'll put some pics up wen I get chance looks very neat.
Regarding fender extender early forks ie 4xv - 5jj use the 1st generation mudguard and no fender extender was ever made - 5pw forks share the same mudguard as the gen 2 so you can get a fender extender for that mudguard. Now my set up is the early forks and I was able to fit a fender extender perfect I'll put some pics up wen I get chance looks very neat.