Andrew,
If the inverter feed wire fuse is good and your have 12 volts at the battery cables at the inverter, but no inverter output. You can try to reset your Prosine inverter by unplugging from shore power an removing the house battery cable for a minute or so, then reconnect the cable. Do not just turn off the battery switch, you need to remove the negative battery cable. If this does not get the inverter back operating, you will probably be inverter shopping soon because a Prosine inverters are not repairable.
Gerald