I grew up on basic visual navigation (and became moderately good at it) but I would not plan a route as depicted if visual means were all I had. It’s too close to CAS and any any type of error or distraction could have you in it. If there were some sort of obvious line feature to keep to one side of it would be easier but that doesn’t appear to be the case.
I agree with other posters about GPS. With the exceedingly complex and busy airspace that has come to exist in the SE of England, it seems a sensible precaution to have some sort of accurate guidance or at least something that will warn you of an impending infringement if you’re navigating the hard way. Those people doing circuits at small airfields, gliders launching and soaring, parachute planes and their cargo, etc. will also be grateful to you, plus you'll reduce the chances of getting star billing in an airprox report.
There are quite a few good planning/navigation packages available, like SkyDemon, and they run on smartphones and upward. Compared to the hourly operating costs of a light aircraft, they are dirt cheap, unlike the fines the CAA can dish out if they think you’ve been negligent...