Hi there,
as theres only two numbers may be easier to just include both of them in the same widget and then use some CSS to hide them accordingly.
So edit the widget with the phone numbers and just add the two numbers like so:
<a style="vertical-align:top;" class="main-phone" href="tel:0000000000"> 00000 000 000 /a>
<a style="vertical-align:top;" class="guildford-phone" href="tel:11111111111"> 11111 111 111</a>
Then this CSS – should hide guildford on all other pages, and the main number on the guilford page:
body:not(.page-id-310) .guildford-phone {
display: none;
}
.page-id-310 .main-phone {
display: none;
}