By William James and Kylie MacLellan LONDON (Reuters) -Britain said on Tuesday it would take all the necessary steps to protect peace in Northern Ireland and urged the European Union to find solutions to a post-Brexit trade row, drawing warnings from the EU not to walk away from the deal. London and Brussels have been trying for months to break a deadlock over the agreement, which in effect created a customs border in the sea between Northern Ireland and the rest of the United Kingdom to preserve the province’s open land border with EU member state Ireland. Britain wants a full overhaul of the…