By Huw Jones LONDON (Reuters) – Britain’s “big promises” to boost the financial sector’s post-Brexit global competitiveness have been a “damp squib”, with many of the changes yet to be implemented and none so far having a substantial impact, lawmakers said in a report on Friday. A year ago, Finance Minister Jeremy Hunt set out his “Edinburgh Reforms” to improve the City’s attraction to global investors, made easier now that Britain, and not the European Union, writes the rules for banks, insurers and asset managers. Pressure to ease rules mounted after UK chip designer Arm Holdings chose to li…