Can a disinfectant solution like Dettol be used for cleaning and disinfecting an aquarium?

That will kill your fish. A lot of cleaning solutions can't be rinsed out completely. To clean and disinfect, you can rub the tank down with white vinegar. It rinses out mostly clean, and the only major change it'll have is that it'll alter the pH, but the alteration is so small you and your fish won't even notice it.