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Thank you for the additional information and photos.

No word as yet on shell width.

71mm would equal Gran Prix.

For a Reynolds tubing model we would expect to see 68mm.

"Usually" Gran Prix has serial on left dropout. Possible that number on shell is from licensing agency. Do not wish to assert this. Mention it only as a possibility.

None of the images show headset; is it the Raleigh -TDC? If you unthread locknut you could check to see if thread 24 or 26 without disassembling.

Expecting 71mm shell and 26 thread steerer...

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