can we stop at the point where ive selected the text or do we have to continue till where they have, giving the answer as a simplified fraction?
I don't have a definitive answer, but I suspect that stopping at your point would be considered correct.
Firstly: you have written v in terms of u, and you have written the fraction in reduced form. There's no instruction to write your answer using a common denominator.
Secondly: if you continue reading the examiner's report for 10(b)(ii), one of the suggested answers involves using v = 8/(u-2) + 4, rather than the version with a common denominator. It would be odd for the examiners to suggest that you should use an "intermediate" step, rather than the correct final answer, from the previous question.