Theragman, since Chambers is the primary reference it would be very risky to enter the answer as it appears in the ODE etymology, especially as that is clearly not in the required form except for one letter.
Cockie, looking at Chambers and Wikipedia I cannot see any difference affecting the letter in positions 2 and 8. However, the penultimate letter is slightly different. It's so minor (almost unnoticeable in Chambers' tiny print) that I doubt that it will be an issue, but I guess I will play safe and enter it as shown on relevant internet sites.
This just confirms my view that the puzzle would have been better without this particular requirement. There are too many uncertainties.