Mark
My advice would be to go for it, as other TMers suggest; but plan for a couple of extra days for the journey. That will allow you time to turn off the motorway, at times, and just enjoy the pleasures of driving your Morgan.
We have taken my 4/4 to France or Northern Spain each year, since first getting the car in 2005 and now can't imagine a year without having a similar journey planned.

Bud
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2003 - 4/4