When I try a search from Safari I am redirected to Bing, not Google. How do I stop this happening?

You have adware/malware installed. Use  Malwarebytes Anti-Malware for Mac. It may be necessary to run more than one scan. After scanning a couple of times, restart the computer and test. If necessary, follow the manual instructions.  Do not download any other programs that are listed in the articles.  

 https://www.2-spyware.com/remove-bing-redirect-virus.html

 How to get rid of Bing.com Redirect - Virus removal guide

Go to Safari Preferences/Extensions, uninstall any you don't recognize, and then turn all extensions off. Test. If okay, turn the extensions on one by one until you figure out what extension is causing the problem.

You are welcome. Most long time posters don't recommend anti-virus or cleaning programs as they can ruin normal operations. I don't run/won't run any defensive programs on a regular basis.

You are welcome.