Sorry about the lack of updates - work has been crazy and I've not really had much to write about in my little world of running, but now I do 
.
So far the running has been going well. I'm slowly building up the "time on my feet" to get my body and feet used to running. This is mainly an injury prevention measure. I'm also trying to stick to the old adage that you shouldn't increase your mileage by more than 10% a week.
At the moment I'm up to 2x 18-20 min gentle runs a week with one in Vibrams and one in shoes, and 2-3 weights sessions in the gym broken up into upper body and lower body workouts (this is actually a major cut in the amount of gym work I used to do so is also taking a fair amount of getting used to). The runs have been going really well and I've not felt the slightest bit of pain or discomfort in either my feet or calves.
That is until I tried something different on Monday. Foolishly, I thought I might see if I can start throwing some speed work in to the mix and to get things going, thought I'd determine my Billat pace (aka vVO2) (mistake 1), in my Vibrams (mistake 2).
I took a leisurely jog down to a nearby park which has a path around it that is about a mile long (mapmyrun.com route) with 100m markers all the way round. As is needed for calculating your Billat pace (I first mentioned it in the context of rowing before), I blasted my way round and managed to cover about 1570m in my six minutes (for those that are interested, that makes my Billat pace about 6:09/mile or 3:49/km). I stuck to the grass verge and actually really enjoyed running fast again, but sadly my legs and feet weren't too happy the next morning.
The muscles in my feet are feeling very tired and my calves very stiff. Based on this, I'd say my form goes to pot when I run fast (need more practice 
) and I really need to concentrate on building my base a bit more, so no more grease-lightening runs for a while.
All in all, the gently-gently approach is working very well and I'm getting in a good mix of shod and Vibram-ed runs and will continue building up a good solid base before diving back into speed work.