The grounds of alleged invalidity
23.The only alleged ground of invalidity was lack of inventive step over each of three items of prior art. They were: (1)German Utility Model No. DE 297 06 007 (‘DE007’) (all argument was conducted by reference to an agreed translation);(2)United States Patent No. 6,590,502 (‘Pederson’); and (3)The advertisement, offer for sale and sale of the Nissen Fahrbare Vorwarntafeln mit LED-Wechselverkehrzeichen product No. 129-265 (‘the Nissen Board’).