Decided the small top box wasn't big enough so managed to find a 49 litre one on Gumtree going cheap, including internal straps & rubber liner. It was in very good nick but one of the old Honda boxes, not the same as my 14-plate 1200 box but still fit the same plate. It was blue but took it to a local painters and they turned it white. Bought a spare key off ebay for £4 and got it copied.
Very happy.