I managed to get the loop working. For anyone interested, code is below. Many thanks
wixPaidPlans.getCurrentMemberOrders()
.then((orders) => {
for (let i = 0; i < orders.length; i++) {
let item = orders[i];
if (item.planName.substr(0, 8) === planName && item.status === "ACTIVE") {
$w('#text35').text = "umi plus member";
break;
} else {
if (item.planName.substr(0, 8) === planName && item.validUntil >= today) {
$w('#text35').text = "cancelled member still within expiry";
break;
} else {
$w('#text35').text = "standard member";
break;
}
}
}
})