Use of the logo here does not imply endorsement of the organization by Wikipedia or the Wikimedia Foundation, nor vice versa.
Fair use//en.wikipedia.org/wiki/File:Royal_Prince_Alfred_Hospital_(crest).png
The crest is of a size and resolution sufficient to maintain the quality intended by the company or organization, without being unnecessarily high resolution.
The image is placed in the infobox at the top of the article discussing Royal Prince Alfred Hospital, a subject of public interest. The significance of the crest is to help the reader identify the organization, assure the readers that they have reached the right article containing critical commentary about the organization, and illustrate the organization's intended branding message in a way that words alone could not convey.
Because it is an official crest there is almost certainly no free equivalent. Any substitute that is not a derivative work would fail to convey the meaning intended, would tarnish or misrepresent its image, or would fail its purpose of identification or commentary.