Two things: I had exactly the same problem as you some time ago, maybe this thread will give you some hints how to proceed. Second: whether you can mix your own bleach and fix or whether you buy some ready made product depends on what you can order from your place and how deeply you want to delve into home brewing.

And one thing right away: just BX1 and water will NOT make a working bleach. You have to either add a source of Bromide to make a bleach, or you add a fixing component to make a BLIX (that's what Tetenal does).