Abscess after pyeloplasty

Abscesses near the kidney diagnosed 4 weeks after laparoscopic pyeloplasty.  Second operation to drain abscesses 2 weeks ago.  Drain tube still installed.  Daily volumes below 100ml and decreasing.  Last week, a test revealed urine in drain liquid. A CT scan a few days earlier did not reveal this leak.  Consultant plans to remove drain when liquid volumes less than 30ml for consecutive days and is confident that the urine leak will heal itself.

If this leak has been there since the first op, is it likely to heal itself after 6 weeks have passed?
Is it reasonable to remove the drain without a positive test to show that there is no urine leak?
I am concerned about closing up the drain with any possibility of a small leak still occurring.