Welcome to Flyertalk BosEuro, welcome in particular to the BA board. It's always good to see new faces here. I do hope you will continue to post.

I can see the problem. W on Finnair is normally restricted economy with low earning potential, and my judgement is that is what you would earn - what is seen on the website seems to pretty much align with what is offered. However it may be a new arrangement, and BA often lags behind any internal realignment of fare buckets by airlines.

I'd be interested to know what is the fare basis here, is it truly WTP? Is this (e.g.) the BA fare bucket rather than the Finnair one? And what route is this?