This isn't true. It was reported in The Guardian that this was the case, but the allegation has been refuted by the BBC - following taken from a number of Reach publications:-
The Guardian previously reported on Friday that the show was intended as a sixth episode to the Wild Isles series and that it had been pulled to avoid criticism from
Conservative MPs and right-wing newspapers. It said insiders at the BBC accused the corporation was bowing to pressure from lobbying groups by broadcasting it only on iPlayer.
A spokesperson from the BBC replied: "This is totally inaccurate, there is no sixth episode. Wild Isles is – and always was – a five-part series and does not shy away from
environmental content.
"We have acquired a separate film for iPlayer from the RSPB and WWF and Silverback Films about people working to preserve and restore the biodiversity of the British Isles."
An Open University spokesperson said: "We are proud to lend our academic expertise and co-produce Wild Isles with the BBC which consists of five episodes. Saving Our Wild Isles is a separate film inspired by the series that was commissioned by the RSPB and WWF and does not have input from the Open University."
A joint statement from WWF, the RSPB and the National Trust said: “Saving Our Wild Isles, which the Guardian article is referring to, is a complementary documentary to the Wild Isles TV series. Saving Our Wild Isles is produced by Silverback, commissioned by WWF, National Trust and RSPB, and will be available on iPlayer.