SVX difficult to start

[gjhumphris]

Well, after hitting a kangaroo in May, I finally have my SVX back from the smash repairers and looking schmick. (I can thoroughly recommend Randall's at Maitland for any panel work - did a great job and took an interest in the car). Worked fine when I got it back, but now it has suddenly become hard to start - it takes about 6 tries to start, stutters and shakes and once it finally kicks over, the red engine light stays on, although runs fine once warmed up. Starting from warm is also no problem, just when cold. It is NOT a battery problem. My uneducated guess is an O2 sensor, but could it be a Knock Sensor (not sure of the difference)? And, is ebay a reliable source to purchase them from?

Any feedback would be great - thanks!