Ah but in the UK - what is the law?

One of our customers now uses a servinr in Cincinati and between the different changovers the e-mail meeting notices got changed to one hour different to the intention. So all but the instigators turned up an hour late and it took a week to prove who was wrong. And the guy who got it wrong is a pedant. Not that it phased him one wit. But we make a mistake and ............