Upvote:1
I'm British and brought my Indonesian partner back to the UK (they had just left the UK after their Tier 4 visa expired) on a 6 month visitor visa for a planned stay of 5 months and two weeks, which we stated in the application. At the end of the stay we planned to (and did) emigrate to The Netherlands, and so made this very clear in the application. The visa was granted without a problem.
I would apply for the 6 month visa and explain in the application why she has not applied for a dependent of a tier 4 student visa, e.g. that she is only staying for 6 months instead of a year.
The UK rarely refuses visas for Indonesians. The acceptance rate is around 95%. This seems to be because Indonesians don't tend to overstay.
It would be helpful if you are very clear in your application what your plans are when the visa expires (e.g. returning to Indo, moving to another country, etc) and any factors which would support that.