Hi so I think you need to achieve 72.7 (rounded up from 72.6 recurring) in your third year to get a first class degree overall. I worked this out by doing 66×0.4=26.4, to work out the weighted grade for second year. Then took that away from 70 (which is a first) by doing
70-26.4=43.6. And then did 43.6÷0.6=72.6 (recurring) because its worth 60% of your overall classification. I hope that is helpful and have included my calculations to explain how got to the number and so they're also there if I've got it wrong.