Based on British Airways you can book some attractive (double) open-jaw flights to China already for £257 (€297). When booking the cheapest solution available you would have an opportunity to visit Oslo or Luxembourg before you would depart to Shanghai. You would then return from Beijing to London. (Non-stop flight). Note that it is not possible to skip first leg of your outbound flight (Oslo – London) otherwise rest of your itinerary would be voided. This is great solution if you want to visit more interesting places during one trip..
if interested in this British Airways promotion you will find the cheapest flights when departing to China till 28th of March. Slightly more expensice also in November 2017. Max stay 12 months and book by end of January.
Booking sample of discounted flights with BA: Open-jaw flights to China from £257 (€297) – return to London… In this case you would depart from Oslo to Shanghai on 19th of March. You would then return on-stop from Beijing to London on 2nd of April 2017. This interesting solution is based on Oneworld carrier British Airways.