Licensing matters are now in the hands of local authorites (rather than magistrates) and all licence applications (and their outcomes) are public documents. This means that your local council has all the details you require. (The easiest way to find out, however, is probably to check the local newspapers. Most of them will have sent a reporter to the local council offices to collate all of the information).
Note, however, that the fact that a pub has got a late licence doesn't necessarily mean it willl stay open late. For example, a bar which has a 'music night' once a month might want to stay open until, say, 2.00a.m. on one Friday per month. The licence application would almost certainly ask for the sale of alcohol to be permitted until 2.00a.m. every Friday but, when you turn up at 11.30p.m. on a non-music night you might well be told "Sorry, we're shut".
Chris