Basically you do the exact same thing twice and in a convoluted looking way. It would be really cool if scalar multiplication and subtraction would be overloaded for points so you could simple write 
```if ( (v_normalised - w_normalised) > eps || (-1*v_normalised - w_normalised) > eps) return false;```

I don't know how difficult this is in practice but it would shorten your code immensely and it would generally be useful. Just an idea.