Thanks for all the replies!
Eddie made it back home this afternoon so have been able to take a closer look and I think it is lots of good and a little bit of bad news.
The Front NS Wheel is about -5 / -10 degrees away from dead ahead whilst the Front OS Wheel is at 0 degrees. Inside the arch there appears to be no major failure of any of the hub components other than the visible distortion to the track so am presuming (cautiously) that the first pot hole was big enough and deep enough to 'jam' the NS Wheel and effectively drive me towards the bank through the damage to the steering track. Given there is only a matter of feet between the first pot hole and the first signs of my wheels being on the bank then at between 25 - 30 MPH this distance would have been covered in no time at all.
The top of the A-Pillar on the OS has taken the brunt of the first point of impact - as I've gone up the bank the Mini has cork-screwed and landed on that point first resulting in the A-Pillar now sitting practically vertical and that side of the car is clearly distorted. There were two witnesses who were driving the other way on the road and they say, similar to how I remember it from inside the Mini, I rolled through at least one full rotation and then I stopped with OS against the tarmac. The NS of the car however seems to be relatively unmarked and, based on my recollection and that of the witnesses, I don't quite know how that is the case but there you go. I was facing the other way when everything came to a halt - i.e. I had to push the front windscreen out in the direction of the oncoming traffic on my side of the road but that could have just been as a result of sliding.
The good news is the engine starts and the auto box will select drive and reverse - I have edged forwards and backwards but for obvious reasons did not want to push my luck but know that the transmission is all OK. All the under-bonnet stuff is intact and even the washer bottle is still in place and full. I haven't lost water from the cooling system and there isn't a drop of oil anywhere there shouldn't be. The bottom arms are straight, the tie-rods are not bent, the gearbox / engine is still sitting level when I look at the car from the front and the suspension is still sitting at the same height either side. As for the rear the same applies - wheels sitting true to the body, suspension at the same height on both sides and is sitting flat when viewed from the back. The box marked fragile that can be seen stuffed in the back of the Mini in the first picture contained all new parts including quad-optic headlamp conversion kit, spot lamp kit, wing mirrors, door handles, rear number plate lamp, headlamp bowls and side repeaters to name but a few and was retrieved from down the road about another 10 feet from where I stopped. That was all the stuff I was going to fit this weekend and, amazingly, not a single thing in the box is broken! 
Since I've got a whole new interior already made up, all new carpets, new dash and my box of exterior bits is still in one piece then I think the best way forward it to move the front and rear subframes, running gear, engine and looms from one shell to another and do a new paint job. Given some of this is beyond my skill set and time restrictions any recommendations of who could do the swap, ideally local to Market Drayton, Shropshire / Staffordshire, would be welcome. Once the new (old) shell is rolling and running I can put everything else back together.
As per the advice I'll be firm with the insurance company - it shouldn't matter too much as I protected the value but that doesn't stop them trying it on!
