Bangladesh uses the Common Law. Sri Lanka uses common law in criminal proceedings and civil law in civil proceedings. Laws relating to marriage, divorce and, I think, inheritance are determined by the ethno-religious background of the parties involved. So Sinhalese use Sinhalese rules; Muslims use Shariah; Tamils use Tamil law; and, I think, Christians can use something else. But I'm not sure how that would make it an example of customary law anymore than Indonesia, Malaysia or Burma which all make allowances for different ethno-religious groups in those spheres. Minangkabau in Indonesia for example are allowed to reckon inheritance matrilineally because that's what they do. I also think Mongolia uses the Soviet legal system.