Hi Northdome and welcome from Liverpool.
I hope you enjoy the C2C. I walked it in May this year and was incredibly lucky with the weather, and, with the exception of the boredom of the Vale of Mowbray part it's a lovely route. I can recommend the Harvey maps, (I got mine from Amazon), though I did plan the route on our OS app, using the Harveys, and then used the phone for on the day navigation - personal preference.
As others have said, the Lake District leg has no signs at all, and the area above Greenup Edge can be difficult to navigate in poor weather - I have directed quite a few of your compatriots over the years up there! Further on there are some areas which use the small "AW" badges on stiles and gates etc, and, as others have said, there are some signs where there are different routes for different seasons.