What U.K. Visa will I need when joining the British army from outside the U.K. Or any other commonwealth country?

I was refused UK family visit visa base on my bank statement. ECO stated that my bank statement is violatile, not sourced and funds limited. ECO stated that my circumstance is very important. First of all am not sponsoring myself, siblings are sponsoring like before when first visited my sister who is a British citizen. I only presented my bank statement to show the amount my bro deposited as a sign of contribution which I stated in my application.i was not give right to appeal, what can I do other than reapply?can I appeal base on human right?