As I've said previously (and many others before me) what we will look at is mitigation for masts and catenary, such as COR-TEN weathering steel instead of bright galvanised masts, where appropriate, and on relevant routes, the provision of twin track cantilevers where appropriate and suitable to hide the bulk of the electrification system behind trees or outcrops of rock.
Standard is bright galvanised steel, seemingly straight off the factory production line.
Could different colours be used like say green? brown? so that they blend in with the landscape. Or is there a specific directive to make them as ugly and visible as possible?
I got to see plenty of Spanish OHLE last week on a tour round.
Here's a picture of an installation on a new (not yet operational) section of high-speed line near Zamora.
The masts (everywhere) are a dark green and are of a lattice structure, and blend in to the background quite well (though the colour of the Spanish meseta is mainly parched brown rather than our fresh green).
The registration gear is unpainted aluminium, and reflects a lot of light (and there's a lot of light!).
They also go in for pulley tensioning, the pulleys being large bicycle size wheels!
Edit: Oh, and all the bases are concrete (no metal piles). Seemingly a totally different design philosophy to the GW project, but good for 320kph.
In looking up some construction history I came across this ADIF (= Spanish Network Rail) video of new lines in Galicia (Vigo-Santiago-Ferrol).
It has some more pictures of their new OHLE.
https://vimeo.com/49824845
At about 20 seconds in there is an aerial shot of the new line and its OHLE, plus more snippets later as they tour the line.
It shows some very impressive engineering on what is just a modest regional line (in the process of being connected to the Madrid high-speed line).