OC-211/OC-183 - contact both IOTAs, order just one Direct QSL
You don't need to order QSLs for OC-211 and OC-183 separately (if you worked both).
If you've made contacts to both islands, you just need order Direct QSL once, putting all QSOs together. It shouldn't be a problem because same callsign VK5MAV/6 will be used. However operation from each island will be indicated and confirmed separately.
http://vk5mav.wixsite.com/dxpedition/qsls