New Carrier not showing up

[djaychela]

I've got a site which is working successfully (ising 1.7.4.2 - I've had issues previously when trying to upgrade, so I'd rather leave things until another time to upgrade),  but I want to add UPS shipping to it, so I'm adding a new carrier.

I have created the carrier, set weight bands with pricing, set size/weight limits appropriately, and when I try a test purchase, the new carrier does not appear in the list for the item.

I have set EVERY parameter (other than the name) as the same as another working carrier for this item (pricing, shipping locations and costs, size weight and group access) to the same as the working carrier, and it still won't appear.

AFAIK I have no modules in place which would stop this from appearing (I only have two third-party modules installed at the moment, and neither would do this).

I've followed a number of 'reasons why your carrier doesn't show up' walk-throughs, and none of those issues apply to me.

Any suggestions would be appreciated.