@ Calimero - They're on 15mm round metal bases from Peter Pig, I can't find a link to the bases on their site, but they've always got them for sale at shows.
@ Barry S - I wish they'd come out sooner, because I'd have bought the whole range, but as I've still got tond of unpainted Essex figures, the Blue Moon are just a suppliment to the collection, but they're certainly worth every penny they cost.