Yes an Abbott did turn over at Beltring - Onto its side - I was there (As were many other people), I have a video of it happening, given to me by someone who filmed it - It went onto its side on the off road course - And all onboard were very lucky to walk away.
If I remember correctly, the driver was covered in oil.
Thinking about the date, It was possibly before 2000 - Will try to dig out the tape and see if it has a date on.
Bob.