how simple is it to replace the seal on a freezer door?

my mother has a broken seal on the door of her Kyoto KU9577 freezer and shes looking to replace the whole machine! I've told her its probably a simple part to replace as the machine is working fine.
Does anyone know if it can be replaced and where I would find the part?
Basically all that has happened is the rubber seal around the door has split resulting in loss of suction hence the door does not seal the cold in.
Any ideas?
many thanks