The signon times depend on the departure time of your flight. You have to report for duty to the flight ops department 45 minutes before STD. Signoff times depend again on the arrival time of your flights but usually not too long after being positioned on stand (allow 30 minutes).
A typical day would be 4 sectors, originating from and returning to Stansted.
Pilots are required to be listed for standby every now and again, if you are called in to work on a day off, you'll be paid £200.
I can't remember off hand what type of flight planning is used but can find out.
The most popular area for STN based people seems to be Bishops Stortford, about 10-15 minutes away from the airport.
I've noticed you're from Australia, there are 2 Australian captains based at STN at the moment.
Hope this helps.