Also find out what state the accounts are like. What work has been done / what needs to be done – whether any reserves have been built up for pending work (for example, where I live there were 5 flats that had to get their roof sorted – the cost was £25k, so each flat had to stump up £5k).
What is included in the service charge (buildings insurance, painting, grounds maintenance, hallway cleaning, etc).
Possibly an important question – what have the maintenance costs been like for (say) the last 5 years? It might be very stable and no surprises, or they could be ramping up to cover things that have been ignored over time.