Advice please: Non fixed place of work travel time; less than national living wage?

steviecasual

i have a friend who works for a large national company where he carries out installations in "non fixed" places of work. He drives a company van and gets paid to travel one way (his first journey) depending on the amount of miles covered. i.e:
15-18 miles = £3.40, 19-30 miles = £6.81..........71+miles = £23.52
Here is an example of a typical day:
0715 - 0900: Travel from home address to site (Miles travelled = 78)
0900 - 1300: Carry out installation at site
1300 - 1330: Lunch break 
1330 - 1700: Carry out installation at site
1700 - 1845: Travel from site to home address (Miles travelled = 78)
TRAVEL TIME = 3.5 hrs
WORKING AT SITE TIME = 7.5 hrs
TOTAL HOURS TRAVELLING IN COMPANY VAN AND WORKING AT SITE = 11hrs 
TOTAL MILES TRAVELLED= 156 
TRAVEL PAY £23.52/3.5hrs= £6.72 per hour (less than national living wage).
Does this seem correct and legal? Some days he could be driving home for 2 hours and not be paid a penny for it. He often doesn't know where he will be working in advance and only find's out on the morning of the same day. 
(Please note he opted out of the 48 hour working time directive when this was introduced) 
I would be eternally grateful if someone could give me some advice? 

Diamandis

The time travelling from, and back to, home doesn't count for pay, only time being counted towards the working time directive. 

oh_really

Why not go into office for 07:15 and then leave for first job from there and return to office for finish time?