My wife and I have three connections to the internet - one PC on which the snipe button is visible: one laptop on which it is also visible - and my wife's laptop - where it isn't visible.
How can I get the snipe button to be visible and working on my wife's laptop? She's the one who does most of the sniping and she badly misses it.

Sounds like you need the browser's extension.

Chrome: https://www.myibidder.com/link/chrome
Firefox: https://www.myibidder.com/link/firefox

Almost certainly!

Many thanks - I'll get it sorted soon.

Cheers
Chris