Disappearing mouse

I have a Q Plus Android 9 TV box which is great except when browsing in any browser the pointer disappears just below the toolbar on the browser.
I've tried Chrome, Firefox, Edge and Opera without success and replaced the standard remote with an MX3 Airmouse.
Any ideas? Thanks

does this have anything to do with screen resolution (screen size/screen fit) ?

Don't think so mate, it appears to be browser based. Any other app I'm using, the mouse pointer is visible. Unless I'm misunderstanding?