The 1 inch handlebar tapered to 7/8" is unavailable and seemingly beyond the capabilities of modern engineering to reproduce. There must have been quite an industry producing tapered tubes in Birmingham in the 1930s, judging by their use in forks and handlebars on Ariels alone but I know that costs of production were prohibitive 15 to 20 years ago.
That leaves you with the option of straightening your bars as best you can but probably accepting an imperfect result - which would be totally authentic for a W/NG, or getting 1" bars from Drags to the original drawings and altering the levers and twistgrip to suit or getting 7/8" bars of the correct shape (which Drags may supply) and putting sleeves in the mountings. Personally, I would go for the straightened existing bars. The W/NG riders might have been war heroes but nobody has ever suggested they didn't fall off from time to time.
36 4G, 37 VH, 53 ex ISDT KHA (project), 54 KH(A), Healey 1000/4 (project)
Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser.