5/10 ak preflop action

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5/10 6-max NL

Unknown villain (1.7k) in SB
Banzan in BB (1.4k)
Hero on Button (1k)

Preflop
folded to hero with A[img]/images/graemlins/club.gif[/img]K[img]/images/graemlins/diamond.gif[/img] who makes it 35 to go,
unknown makes it 75 in the SB, banzan cold calls, action on hero ?

In the actual hand, hero felt that it might be worth trying to take down preflop.

Hero made it 300, SB pushed, banzan folded ... hero ?

Comments on all points would be appreciated