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Would this grow in my limey clay soil Andrew

While the lime would not be a problem, heavy clay would not be to its liking. But if you were able to include lots of bulky organic matter to allow the roots a good run, then it should be fine.
Two things to point out on this one. Firstly, like all clematis it prefers shade at the roots and its head in the sun. This is most important as it comes from the Balearic Islands in the Mediterranean where it gets a good baking. After the hot summer of 2006, it flowered its socks off last spring. Secondly, as a defence against the hot, dry summers in its native environment, it goes into a summer dormancy (from about July to September) so don't be surprised if it doesn't look hapy in the summer - it will come back again in autumn