VSS is spot on, its certainly not a notifiable disease, it does make me wonder where people get there information from and I certainly wouldn't have taken a lamb to market with orf!! If you haven't got a serious problem with it don't vaccinate, its a live virus and a horrible little sod!!
We have a good success with Ovaloid Capsules they can be given to both ewes and lambs, we give the lamb two capsules, then we spray the area with Terramycin spray and for good measure give a jab of long acting Terramycin or similar, its a bit "belt and braces" but it saves me having to keep inspecting the ewes/lambs.