These books have excellent coloured plates;
archive.org/details/birdsofbritish00cowa (http://archive.org/details/birdsofbritish00cowa)
archive.org/details/birdsofbritishis00cowa (http://archive.org/details/birdsofbritishis00cowa)
Examples;
archive.org/stream/birdsofbritish00cowa#page/n7/mode/2up (http://archive.org/stream/birdsofbritish00cowa#page/n7/mode/2up)
archive.org/stream/birdsofbritishis00cowa#page/n7/mode/2up (http://archive.org/stream/birdsofbritishis00cowa#page/n7/mode/2up)
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And here's one for British amphibians and reptiles;
archive.org/details/britishreptamph00simprich (http://archive.org/details/britishreptamph00simprich)
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