I cannot call to mind any other city, or large town, in the UK that is referred to by the name of the river on which it stands. (The Hull River joins the Humber at Hull)
Before anybody replies, I do not count the many ?????mouth around. Hullmouth sounds a bit crass.
I think that it would be churlish of the quiz checkers to exclude from the raffle any answers using either Hull, Kingston-upon-Hull and its variants. Particularly as the 'large town' is a city.
But, they have made mistakes before and refused to retract. As it says on the tin, they are the judges and they have the final and only judgement. It is their quiz after all.