A 26"-wheeled machine would be a Raleigh Dawn, if here in the States. Unusual to find at any rate, though I'm perplexed by the orange color. I know Raleigh produced the Rudge Aero in a shocking orange/black combination, but I've never heard of it on a Dawn, or a Sports for that matter.
If it is all there, and if you're absolutely sure of the color being original, I'd go for it. If it is something that won't be sold anytime soon, take a photo of it and post it up here before taking the leap. If it's on Craigslist, just get it.
-Kurt
P.S.: A variant of the Dawn was produced in the early '80s for the U.K. market only under the name Raleigh "Royal Roadster." DL-1 based models were also produced under the Royal Roadster name. Regardless of the variant, these only came in black just the same.