Newish lawn

My lawn was laid on 17 April, and seems to be doing ok-ish. I watered it every evening for at least the first fortnight and that was at a time when there was some rainfall from time to time. Recently, I haven’t been watering it but plan to once a week now, as the forecast continues dry.  One particularly dry patch in the upper right of one of the photos is under an elder tree, so I get that, and the photos look more patchy yellow than to look at them.  

Question: I usually mow it every week and a half on average, as those neighbours mowing well established lawn weekly look virtually all yellow. 

Any my thoughts or recommendations would be welcome. Thanks, Chris