If you seriously want a set of banded RRs, take my advice and just buy new from someone like Duchy, unless you know someone selling a nearly new set of Duchy's.
Reason being is banded steel quality can vary and myself and a few others have been stung buying used Banded steels that are buckled or not built very well, or just rusted out to a point where you cannot really have them refurbished because they are so pitted.
RR's are expensive, but they do tend to hold their value better than buying new alloys. My recent pothole tyre damage on my RRs made me wonder if I should get rid and move back to Banded Amaroks, but every time I sell a set of RRs, I regret it, so they are staying this time.