\chiseller, the answer to your question is yes, it is a lime hawkmoth, as far as I can tell.
A quote for the UKmoths website"The larvae feed on lime (Tilia) as well as a number of other deciduous trees including birch (Betula), alder (Alnus) and elm (Ulmus). They are typically green with yellow stripes and a blue horn at the rear. When ready to pupate, they change colour to a dull greyish or purplish and begin to wander, looking for a pupation site. This is when they are most often encountered."
Tiptop cheers :thumbup:
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