One of the many major inaccuracies of the Revell "Thermopylae" concerns the hull shape. The real Thermopylae's hull lines were significantly, noticeably different from those of the Cutty Sark. Among other features, the Thermopylae's forefoot had a much bigger, wider-radius curve to it, and her stern counter was much more delicate. (The Cutty Sark''s powerful counter was one of her more radical features - one that put her in particularly good shape for the Australian wool trade.) The hull in the kit is a green version of the Cutty Sark - and that's all.
There were also numerous differences in the rigging - and even more differences between the spar plan of the real Thermopylae and Revell's imitation of her. The removal of the studding sail booms is inexplicable (the real ship had them), the rendition of the deadeyes and chain plates is nonsensical, and the real ship had, if I'm not mistaken, at least one patent-rig, "self-furling" topsail or topgallant.
The best information about this ship that I've bumped into is in two books by David MacGregor, Fast Sailing Ships and Tea Clippers. Mr. MacGregor provides a set of reconstructed plans, and at least one photo (from the ship's latter days, when she was painted white).
Frankly I'm not at all sure that "accurizing" the Revell kit would be significantly easier, or less time-consuming, than working from scratch. The Revell folks really pulled a scan with this one.
The old Revell Flying Cloud, on the other hand, is a beauty - even by modern standards. I wish Revell Germany would re-release it. (I also wish it was on a bigger scale, though.)
Youth, talent, hard work, and enthusiasm are no match for old age and treachery.