Top of the range touring bike I'd guess around early 80s. As said above there should be some component dates which will give you a good idea.
The style of the Dawes decals suggests that period, also it's from the pre-cantilever brake era of Galaxies/Super Galaxies; cantis (ditto gear lever bosses and mutiple bottle cage mounts) appeared on those tourers in the mid-late 80s....I think.
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