Any reads on villian or stats? If he is semi-tight then I might fold to the check/raise but if he is capable of making a lot of plays then your flat seems fine or you could even 4bet smallish since you are original raiser UTG. If you flat you are gonna probably call a lot of turn cards/bets unless they are absurd but then that makes the river decision tough in a lot of cases. I almost prefer a 4bet on this flop and fold if he comes over the top of it. You are just deep enough and it actually is cheaper/stronger considering any turn bet from villian is likely 1500+.  

agree that cbet size should be bigger, as hape says quite often like to cbet less than half pot and just click the 45% button I have set up on stars and when multitabling quite often dont pay enough attention to this, 475/525 sounds way better…

FWIW 13 hands with villain 2nd hand he'd played – stats 8/0

I called as I thought I may still have the best hand and it could slow him down with pairs under a Q, or Q's that arent AQ (not ever really expecting a 4 in his calling range), after all its a good flop for me to cbet without connecting

like I said AQ is a good part of my range UTG – get a check on turn and maybe call a bet on river if I dont improve and the board blanks / doesnt look too scary….