suswin

Virgin now costs over 600 GBP for return to HK. As far as I knew, there was no special offer since 01MAR.
Virgin sells open jaw return ticket, outbound flight to Shanghai and inbound flight from Hong Kong, costs same fare, over 600 GBP.
Sorry, Virgin does not serve Bejing itself (codeshare with Air China only), in your case, you can only fly with BA which sells open jaw return ticket as well.