Hi Rob,
Congratulations! If you haven't done so already, you need to get in touch with the Detomaso Driver's Club in the UK. They are a very active group with regular meets, and have all kinds of contacts that could come in handy if you need parts, advice, or sympathy.
Regarding buying a car sight unseen, I purchased my GT5-S unseen from Franz Krump, who ironically has posted just above me here. Long story made short - I understand your nervousness but in my case it worked out very well, and I made a new friend in the process. (Hi Franz!!)
Good luck!
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