You could also visit the Harvey Maps website and download their pdf catalogue which contains decent sized examples of their mapping at different scales along with a list all the products available.
The on-line BMC shop also has good prices if you are a BMC member, but a restricted offering. The Dash4It website is offering a 20% discount on all Harvey Maps.
It also appears that if you download the free Avenza Maps app you can then download a couple of free samples of Harvey mapping of the West Highland Way and the North Downs Way to have a look at the cartography.