Native speaker commenting, we say 请拐左.
better translation 请向左转
转 translates to 'revolve'. Humans don't generally take that verb, unless they are literally spinning around in circles. '拐‘ means to turn.
I think the 走 is unnecessary
Whats this mining of?
If you remove 走 from this sentence you are left with ’Please in the direction of left', which is nonsensical. You need a verb, and although I wouldn't say this was the right one, removing it completely is not the answer.
Shouldn't 请左转 be correct?
Surely this would be 'please walk left', to 'turn' would be 拐.