I see. So this is the ECU! Then the other smaller boxes must be the tuning control units for Petrol and CNG.
Also, the problem was solved by 'repair' of this ECU...
The electrician told me that over the past 15-20 years, he has had many such 'repairs' done. Models affected are Liana, Baleno and Cultus (All EFI ones) and he has followed the cars for as long as 2 years after the repair with no evidence of the problem re-appearing. So I have my fingers crossed too 
Many thanks umarkhan1 and pomi_pbs 