this would work for a chest freezer and has been discussed before for making a low power fridge but if you tried it with an upright freezer like you suggest you would have the same energy sucking downfall as regular refrigerators have that is every time you open the door the cold air sinks out the bottom and is replaced by warm air flowing in from the top forcing your fridge to have to run to cool all that cold air it lost every time you open the door.
second if i needed one of those i would not order one from Australia i would go to my local johnstone supply walk in the door walk up to the counter and say "pardon me could i have a current catalog??" then i would go home and look though the catalog and find the replacement thermostat with the specs i need go back the next day and buy it by part number. be allot cheaper than ordering out of ozz. or you could just pull out your old thermostat take it in and explain exactly what you want they will match one up for you. only difference is that way they are likely to charge you retail for it instead of catalog price.