Two parties to a contract fell out over what 'close of business' meant. A notice was served at 6:02pm, but the receiving party argued that 5pm was the appropriate time that a reasonable person would consider to be close of business.
The Court held that it is the receiving party who needs to specify those hours to the party giving the notice.
The lessons? If you want a notice provision in a contract to be served within your business hours, it is up to you to specify what time that is!
The case? Lehman Brothers International (Europe) v Exxonmobil Financial Services BV  EWHC 2699
The Court said that it was on the party receiving the notice to establish when it closed for business, but it had failed to do so.