The UK Defence Logistics Organisation asked industry for expressions of interest to undertake the re-winging work on up to 10 aircraft, which was expected to take between 18 and 24 months and cost £20-100 million ($39-195 million).
I hope that time & cost estimate is for the entire 10 aircraft, but knowing Marshalls, I wouldn't be so sure.
Lockheed claims approximately 9 months & $9M USD for a re-do of the centre wing box which bears the brunt of the load.
If they're just going to re-do the outer wing planks, it seems a bit high...
The AC-130 article mentions the replacement of the CWB in the MC-130H at the bottom. These will hit the wall much sooner than the AC-130 trainwreck...glad to see they've finally allocated money for this.