Iron Domokun said:USS Valiant: A USS Valiant is listed in several Trek episodes, including the Original Series episode A Taste of Armageddon where it went missing. Apparently it also was mentioned in later series. I don't know if this is a license issue or not; just bringing it to your attention.
If you wanted to change the name to something else, I propose Hood (NCC 1707) as a possible replacement; Hood was destroyed by a squadron of Klingon cruisers on Day One of the Klingon Invasion in 2571, and the illustration fits neatly into that story (presumably the third Klingon cruiser is out of frame). Hood is also a name familiar to British audiences.
They'll probably be ok with it, to be honest - all the Con-class CAs were listed in the Technical Manual which I think they had an open-ended license to use anyhow...
Mind you, I'd be more than happy with the Hood... it was my ship in an online RPG group, albeit a later era and a different class...