We have worked with Clients who have achieved ISO 27001 in 3 months and others who have taken a year to obtain it.
Our ISO27001 Advantage programme typically runs for 6 months. The weekly calls are just 60 minutes, and you control the pace of implementation. Some clients complete it faster, others need a bit longer but the aim is to obtain certification within 6 months. If you are able to tailor documents and get the evidence to support the certification in place, then you can achieve the certification quicker.