Technically since you were having foreign investment and since this investment are monetary item as per IndAS 21 the value of monetary items needs to be updated to the closing rate at end of every financial year and therefore you should have recorded the foreign exchange gain every year.
However since you have not done that it can create some problem.
Ignoring that i guess 300000 should be foreign exchange income as it would have been recorded every year and 80000 would be profit on sale of investment for book profit purpose.
I dont think this transaction will affect consolidation as the gain has been realised in monetary terms and it is not any unrealised profit as in case of stock transfer etc.
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