Unlocked-mobiles.com is now taking pre-orders for Nokia Lumia 1520 unlocked device for £594.98 including taxes. This is not a final listing price as they have mentioned in their website that pricing is yet to be confirmed. They have also mentioned an expected date of arrival as Nov 25th which I think is highly possible. Nokia is set to launch Lumia 1520 for AT&T on Nov 22nd along with its Lumia 2520 tablet. So, the Nov 25th date for UK launch of Lumia 1520 may be correct.
Other retailers and carriers in UK are yet to confirm about the Nokia Lumia 1520 launch.