It is not necessarily cowardly to take the lower offer.
One sometimes has to play strategically, say one has only attained two questions right making for a £2,000 possible win and the chaser offers £1,000.
It is much more beneficial to go for the lower figure (especially if there is a large pot already), and get back to join the others, it then gives the other contestants another point start and another head to push the Chaser back.
Same as if there is only one contestant left, and all the others have been eliminated, it is much better to go for the top figure, after all what has one to lose if the Chaser catches them, which is quite usual, they still have a chance of winning £1,000 each when they are all brought back.