Thanks for your reply. I found this..
Immigration Rules Appendix FM-SE: family members specified evidence
https://www.gov.uk/guidance/immigration ... d-evidence
32D. If an applicant applying for limited leave to enter or remain under Part 8 or Appendix FM submits an English language test certificate or result and the Home Office has already accepted it as part of a successful previous partner or parent application (but not where the application was refused, even if on grounds other than the English language requirement), the decision-maker will accept that certificate or result as valid..
I think it should be Ok.