Bush gave this tour of the White House(link below)and the Winston Churchill bust is spoken about briefly.
To me the video is quite refreshing, the former president does a very nice job giving the tour and he seems to carry himself quite well.
The bust is shown and spoken about after the 5:30 mark and the thing being "on loan" is mentioned 2 times.
Here is a related video of the current President speaking about the Oval office, another informative piece IMO.
Hopefully his placing a bust of Martin Luther King Jr in the office doesn't upset too many viewers.