Starman,
Maplin (site won't let me post URL but its the obvious at .co.uk) will supply the bits relatively cheaply:-
US 2-pin plug: Maplin part no. HL17T (?1.39 per each);
US 2-pin coupler: Maplin part no. HL19V (?1.49 per each);
suitable cordage: Maplin part no. XR47B (?0.59 per metre);
Other suppliers may be cheaper, but Maplin have the stuff in stock and will post it to you quickly; and it will still be cheaper overall than buying one on eBay.com and paying postage from USA.