Hello everyone,
Firstly purchased second hand Omega 3.0 V6 on a T plate at 74000 miles good service history in January this year.
Now the problem went to work Monday morning from Kingston Surrey to Cambridge finished job at 2.30 am went to start car and flat Battery

Green flag came out and got me started everything was ok, got home around 5.30 am switched off the checked to see if she would start again sure thing sprung into life, oh well must've left summit on.....
No work Tuesday went out to car at 5pm just to check if she would start an sure enough sprung into life ok I think all is good.....
Wednesday morning off to Cambridge again started first time all was good on the way to work no obvious problems apart from noticing the automatic gear box seemed to be hunting for finnal gear at high revs during kick down and overtake strange I thought.
Wednesday evening 6pm left work heading back to Kingston Surrey all was good for about 40 miles then power steering begins to get heavy, then Battery warning light comes on, then temperature warning light comes on and temperature hit 100 for less than 5 mins before I could get her on to the off ramp hard shoulder on the A1m to Luton airport (hopefully no permanent damage done pipes seem all ok expansion tank has dumped its contents fingers crossed)
Green flag checked and confirmed its the auxillary belt plus the tensioner/pulley.
Looked at pictures of what the pulley should look like and mine is missing the v knotched wheel must've completely shattered causing the belt to shred up. Little bit of plastic scuffage to the cover behind said pulley wheel assuming I'm right that would be the timming belt cover.
So my questions are,
1. Have I done more damage for the less than 5 minutes to get her safe fingers crossed hopefully not.
2. How easy is it to replace and any special tools needed to do this myself.
3. Is there anything else aside form the obvious that whilst I'm there and she's all in pieces I should also check condition of and or change.
Thanks in advance for any help on this matter of urgencie.