Chemistry Calculation Question

I titrated a standard solution of potassium iodide (250cm3 0.001 moll-1) against a standard solution of sodium thiosulfate (250cm3 0.0249 moll-1) as a positive control for my experiment about determining the iodine content of different seaweeds.

To see how far out my procedures are I am trying to calculate how much iodine there should have been in my potassium iodide solution. This had had 10cm3 of H2O2 (20vols) added to oxidise the iodide into iodine. Then 25cm3 of cyclohexane was added and the iodine moved into the cyclohexane. Solvent extraction was used for this. The solution of cyclohexane with the iodine in it was what was titrated. The average titre volumes were as follows:

1) 8.4cm3
2) 10.45cm3
3) 11.0cm3

I can't figure out how to find how much iodine there should have been in the samples? I would be very grateful for any help,
Thanks