I had similar case. Once I had an interview they said I will definetely be based in Riga and I was completely fine with it. but when I received contract it was Helsinki already.
Btw maybe someone knows anything about base bidding in Norwegian? what has to be done and is it even possible for new pilots? Have heard that it depends on seniority and also preffered base?! and at the end of the day- maybe it's possible to swap base with someone who agrees?