The linked article doesn’t go into detail about why there was an attempted right-wing takeover so here’s a TL;DR from this Guardian article:
Restore Trust opposes what it describes as a “woke” agenda – including National Trust displays about slavery and historical figures – and has said it wants to steer the charity “back to its core purpose of looking after our heritage and countryside”.
[Restore Trust] was led by a group of longstanding National Trust members “who are concerned that the NT has abandoned its original remit and is now, like much of the charitable and third sector, pursuing a politically motivated ‘revisionist’ agenda”.
How dare the National Trust, who owns more than 200 historic houses, want to teach people about history? /s
It’s just blatant vice signalling. So, yeah, glad to see this attempted takeover failed.