$L7 bubble c-bet the nut flush draw?

[Little John]

sb/bb were unknown, seemed avearge. i had not been out of line.

PokerStars No-Limit Hold'em Tourney, Big Blind is t200 (4 handed) Hand History converter Courtesy of PokerZion.com

BB (t3465)
UTG (t1850)
Hero (t4375)
SB (t3810)

Preflop: Hero is Button with A[img]/images/graemlins/diamond.gif[/img], 5[img]/images/graemlins/diamond.gif[/img].
<font color="#666666">1 fold</font>, <font color="#CC3333">Hero raises to t500</font>, <font color="#666666">1 fold</font>, BB calls t300.

Flop: (t875) 8[img]/images/graemlins/diamond.gif[/img], Q[img]/images/graemlins/diamond.gif[/img], 4[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
BB checks, <font color="#CC3333">Hero?