This View Quest GPS Sat Nav with 4.3" screen comes with full UK maps. It has a large 4.3" colour TFT touch screen, with 480 x 272 resolution and is amazingly 11.9mm thin. Whilst driving the navigation continues to work when in tunnels and uses simple visual and spoken directions to get you to your final destination.
This is really easy to operate and cheap as chips.
Dont forget cashback and pick up instore to avoid delivery charges.