By Huw Jones LONDON (Reuters) -The European Union’s 19 trillion euro ($21.6 trillion)investment funds industry is failing to exploit the bloc’s single market, saddling investors with high costs and opaque selling practices, the European Court of Auditors said in a critical report on Monday. A full review of EU investment fund rules is needed by 2024 as minor revisions will not be enough to create a better market, according to the independent EU body which looks after the interests of the bloc’s taxpayers. The EU’s single market seeks to tear down cross-border barriers to trade and offer custom…