Due to changes in Immigrations operations the file has been transferred to the London office for processing and due to their workload they have informed you the timeline has changed to 6 months.
When applying without a job offer it can and does take many months for an application to be assigned a case officer as the file is not a priority to them (as it has no job offer associated with it).
You have not yet been assigned a case officer and the timeline will be from when the file was received in London, but it is just a timeline and nothing concrete. It is a guide. You could have a CO assigned next week but on the flip side it could be 6 months or more.
There is nothing you can do other than wait patiently and maybe send Immigration Customer Services an email reminder every once in a while although it would be better if you contacted them by phone as always better speaking to someone directly.
EOI submitted Jan 2010. ITA Jan 2010. ITA submitted Apr 2010. RV approved June 2011. Passports stickered and back to us Aug 2011. Secured job Dec 2011. Arrived Mar 2012. PRV Mar 2014......now eligible for citizenship but at $1175 Yeah but Nah!!!