Thanks for all the thoughts everyone. I'll try to answer your questions or clarify points the best that I can:
Lightning Chaser- I would say that I was 2-3km away at the time. The wind I was experiencing from memory was generally travelling in the same direction as the storm.
John Allen- The shot was taken with a 10mm-24mm lens @ 10mm but because my camera (Canon 60D) is not a full frame camera it has a 1.6x crop factor giving a focal length of 16mm. The feature when I first observed it from my car appeared to be basically an extension of what is in the picture. No widening at the base that I could see. I have not been back to the area to look for any damage.
Jimmy Deguara- Can't help you with a video. Might have to treat myself to a video camera soon
I should point out that my interests in storms at the moment is from a photographic point of view, rather than from a scientific point of view. So instead of taking a series of shots after the initial quick snap, I was more concerned with recomposing or finding interesting foreground structures. I'll attach another one from the same storm taken a few minutes later, but apart from that, like Jimmy says we will have to leave this at the moment due to the absence of further evidence. Again thank you all for your feedback. Hopefully I'll have another opportunity to properly document another event soon.