I dont think that you have calculated the effect of the share split correctly.
The numbers in your post are not clear on a few points.
You say you sold all 4000 shares at 1.80 a share, but you owned 8000
Did you sell 8000 shares at 1.80 a share or 4000 at 1.80 a share and still hold 4000 ?
If you sold all 8000 at 1.80 a share, then the following figures should be correct.
You got 4000 shares with a market value of 0.6 = €2,400
You sold 8000 shares at 1.80 a share so you got €14,400
Therefore the gain is €12K.
25% of 12K is 3000 - 1270 = €1730