These go on ebay with lots of original parts for about half what you're asking:
http://www.ebay.co.uk/itm/retro-raleigh-carlton-super-course-racing-bike-frame-suntour-cyclone-gears-/301292737765?pt=UK_Bikes_GL&hash=item46267254e5
The one in that link is Raleigh made. This one looks like the one build before Raleigh bought Carlton, i.e. made in Worksop as the OP states. That means better quality, so, for me, the price is fair.
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These go on ebay with lots of original parts for about half what you're asking:
http://www.ebay.co.uk/itm/retro-raleigh-carlton-super-course-racing-bike-frame-suntour-cyclone-gears-/301292737765?pt=UK_Bikes_GL&hash=item46267254e5