<Dons anorak>
The names for the Type 45 all have some heritage behind them.
'Duncan' is the seventh to bear the name and there was, IIRC, a 'Duncan' class of battleships from about 1901. The name commemorates Admiral Duncan , who defeated the Dutch fleet off Camperdown in 1797.
We could also get a 'Diana' (presumably HMS Saint Diana to move with the times....) 'Dainty' and a 'Decoy'. Which would be a 'Delight' (again, all 'D' Class ships)....
<Anorak off>