Taxis at 6AM

After getting some great feedback from this group, we decided to fly out from BLQ to LHR instead of trekking back to Milan. The flight we are looking at will leave BLQ at 8:45AM. We will likely need to check a bag and it will be myself and a child. A couple questions:

1. Would leaving our central Bologna hotel at 6AM provide enough time?
2. Are there taxis readily available at this time? Our hotel is offering to set up a ride for us but they want 55 EUR, which seems excessive for a 15 minute drive.

Thanks!