Bandwidth Issues when Participant shares Screen

I host Zoom Meetings in a hall for my Camera Club. We've had no problems when using my Laptop, but have consistently had issues when using a brand new laptop.

Problems occur when a participant shares their screen, to show images during a lecture. With no "low bandwidth" warnings, the audio (voice) from the participant breaks up.  We have noted some improvement if we disable any recording. 

Switching back to my laptop (2 out of 2) has fixed the issue.

The club laptop is a good spec machine. It handles all other tasks well - photoshop, lightroom, etc, but not Zoom. The WIFI in the hall is good and clearly no problem with Zoom on my older machine.

Any ideas or thoughts would be appreciated