My LCR can get anything from 22mpg to 38mpg on a long slow 50-60mph run. In traffic it's at it's worst. Typically I get an average of 32mpg on a mixture of town driving and A roads.
Regarding insurance I am under £300 a year with Admiral or Elephant. I change between them most years to get the best deal even though they are the same company. Thus year I took out the multi car policy and it's only £230!