BRITAIN and Ghana are close to announcing an agreement on post-Brexit trade but a deal will not take effect in time to prevent a period of operating on default terms, according to a source close to the negotiation. Once active, the deal will replicate the terms of trade Britain previously benefitted from as a member of the European Union. EU trade rules will cease to apply to Britain from Jan. 1 when it completes its exit from the bloc. Ahead of that deadline Britain has signed "continuity" agreements with 63 countries to safeguard terms on 885 billion pounds ($1.21 trillion)…