If Liberty Global wants a mobile operator to complement its Virgin Media cableco in the UK, it may have a choice of dance partners. According to reports, Telefonica has been courting the US group as a possible buyer for its O2 UK arm, whose takeover by Hutchison was blocked by competition regulators last year. But other reports, also sourcing unnamed company sources, claim that Liberty is back around the table with Vodafone to negotiate a UK merger. A deal between Vodafone and Liberty has been reportedly on and off the table for a couple of years, and there has been persistent speculation about a full-scale merger of both groups, or of their operations in individual countries. They already have a…