(Reuters) - London's FTSE 100 joined a global stocks rally on Monday driven by rising hopes of a U.S.-China trade deal, while baby products retailer Mothercare sank to a record low after appointing administrators for its UK operations.The FTSE 100 added 0.4% as Asia-focussed banks HSBC and Standard Chartered as well as miners including Rio Tinto firmed after Washington and Beijing signalled they had made progress in trade talks. The mid-cap FTSE 250 also advanced 0.4%.Struggling retailer..