Futures Rollover settings and price

[RichardSmith]

I searched the forums and didn't find the answers to my questions, apologies if it has already been answered.

1. What setting is by default when holding a future position in spread betting account - rollover or what happens when the contract expires?

2. How do I know when the contract expires?

3. What happens on roll over, specially if there is a big gap between futures prices e.g. VIX Mar 20 price atm is 77.80/78.00 while Apr 20 is like 62.30/62.45 What happens when the contract expires? Does the March position get closed at at last price and opened at Apr price which say is 63 instead of 78?

4. Thank you in advance