Is there currently a hack on here or a map update for the UK roads? I have stalked here for a while but never piped up to talk.

Read through this thread

http://avic411.com/index.php?/topic/81488-2015-european-map-update-for-pioneer-avic-f30bt-f930bt-f9310bt-f40bt-f940bt-f840bt-f8430bt/

I think this will give you what you want, I'm fairly sure someone reports doing a F20-BT, just read the thread fully first

post 407 reads the theme
http://avic411.com/index.php?/topic/81488-2015-european-map-update-for-pioneer-avic-f30bt-f930bt-f9310bt-f40bt-f940bt-f840bt-f8430bt/page-28