Welcome to the forum from a wet Devon.
The lack of signposting is because an official C2C doesn't exist. When it was first mooted by Wainwright, the idea was that walkers found their way from one coast to the other. Over the years "routes" have grown up but you are still at liberty to make your own route. If you look on an Ordnance Survey map you will not find the C2C marked at all so for example, when you get to the first of the Lakes, Ennerdale Water, you are at liberty to follow either the N or S bank. The same philosophy applies right across the Lakes.
That said, you will find signs from time to time indicating the way or, as in the case of crossing the moor S of Kirkby Stephen, directing you on different routes depending on the time of year.
UK mapping is good and, if you are a competent map reader, you should have no difficulty. While a C2C signs may not always exist, paths are often signposted and by and large the route is well trodden, but do not expect waymarking as in many European countries.
Enjoy your visit.