Someone hit my car in the rear drivers side about 4 months ago. The insurance company fixed the car. After about a week I then started noticing that the steering didn't feel right. Seemed to be mainly at higher speed when turning, the car wanted to go straight. The other day I got a wheel alignment check and the garage says that the rear left wheel is out quite a lot (0.27'). I want back to the insurance company and they are looking into it. They sent me an alignment check just before the car was returned. That says it was 0.17' and the limit is 0.19'. It seems that it was near the limit anyway and just got worse. I have been told that the toe cant be changed on the rear. Is it a case that they have to change the back end components? I am not sure if the insurance company is going to try and blame this on me. I haven't actually done anything like drive into a kerb, so not sure how it could of got that much worse. But then I am not a mechanic so maybe there is a reason for this. 

This is very odd.  The Fiesta uses a solid rear axle, so there aren't any parts that can cause the toe to get worse without being hit.

The only thing I can think is that the axle mount has come loose from the chassis on that side and the whole axle has now twisted, but that would affect both sides, and the wheel would sit further back in the arch too.