I had five points put on my licence in May 2015 how long do they stay there

It depends on the offence - see https://www.gov.uk/penalty-points-endorsements/how-long-endorsements-stay-on-your-driving-licence

Although depending on why you're interested, how long they're on your licence might be the wrong question.

For example, if you're interested for employment purposes, take a look at this - https://hub.unlock.org.uk/knowledgebase/motoring-convictions-and-the-rehabilitation-of-offenders-act/