Not really sure the overall source of these pictures, but thanks to Lee for sending them in.
A Shield-Captain, Vexilus Praetor and Allarus Custodian.
This could be an HQ set for an upcoming Adeptus Custodes Codex. All the armour looks slightly different so it could be that this plate is Artificer or Relic.
Hopefully Kaelo will have more info tomorrow at WHW.