as bigtom said, it depends on what your plans are..
i take it if you need to take the test and your married, your on a 2 year spouse visa ? .. if so, like you said you need to take the test

and before you apply for ILR, or if you don't you need to apply for FLR for 2 years.
whats wrong with dual nationality ? .. then your free to go and do what you want without any restrictions. ILR has restrictions on how long you can leave the country, and also you stll can be refused entry clearance by an immigration officer at the airport
