It seemed like a lot, but I went ahead and did it!
Only when I returned and checked Marius's training program did I find I should have done only 4 not 7 reps, Oops!
using my Hillside loop I set off after a warm up into my first effort, 3 mins at L2, [which for me is 6.48 pace, about 30 sec below my marathon pace], after 3 mins I accelerated up to L3 [ marathon - 1/2 marathon pace] for another 3 mins, then the last 3 mins required another acceleration up to L4 [ 10k pace]. This was followed by 2 mins easy before the next set of 9 min efforts, easy right :]
I have to say I had a bit of trouble trying to hold L4 pace which should have been at 5.44 pace, maybe subconsciously i knew I had a long way to go so held myself back a little, anyway finding out I only needed to do 4 and not 7 reps made me feel a lot better :]
1 hour 26 mins inc warm up and down and 6 x smart strides

I wore my Spira Competition shoes for the session, not worn them for a while, I still really like them. At 220 g they are ultra light and flexible, yet the spira springs absorb impact amazingly well, my Newton's feel really heavy and restrictive by comparison, so I reckon on using the Spira's in my next Marathon!
I think the way to go is; Do most of my training in very minimal shoes, so my feet and legs can get as strong as possible but use a shoe like the Spira in races so I can run as fast as possible with the least amount of impact to my body.
Less muscle damage means faster race times!