Estimated time to migrate a line from BT to Plusnet

[#1]

My BT Line Rental Saver ends on September 22 and instead of renewing I plan to migrate to PlusNet's equivalent.  I'd like to time my order to minimise any dual payment; what's the typical turnaround time from ordering to the line switching?
Thanks!

[#2]

Hi there,
The lead time for a line transfer (WLT - Working Line Takeover) is two weeks.
We're not able to do this any faster due to Ofcom General Condition 24.

[#3]

...and if you want to read it http://stakeholders.ofcom.org.uk/binaries/telecoms/policy/narrowband/statement.pdf

[#4]

Thanks guys, I'll place my order on September 7