Due to the lack of foresight, I booked a return ticket to take advantage of a price discount, and hence the limbo in Europe for another week.
Closer to departure, I again received an offer from Finnair, this time round for an upgrade on the Zurich - Helsinki leg.
While I might struggle to make a decision had it been an offer for the Helsinki - Singapore leg, it was almost a no-brainer to turn down this offer.1. It is a 2 hour short-haul flight
2. Business class on most intra-Europe flights is essentially economy class with a blocked middle seat
3. Hence it would be ridiculous to pay EUR69 for such upgrades, given that an one-way trip would probably cost less than that.