Nippon Izakaya, North Finchley: Consistency needed if this place is to survive

I have been to this Japanese Restaurant, usually at weekends, twice before, and it really hit the spot. Good food at a fair price, and what was supposed to be hot was actually hot.
I recently went at 8pm on a Wednesday towards the end of August and it did not live up to expectations in many ways: so much so, that I might give it a miss in the future.
There is a web site on https://www.nipponizakaya.co.uk/ and it tells you that it is a non-chain Japanese restaurant in North Finchley. Strangely enough there are quite a few to choose from in the area, and given that the Japanese are long departed from Woodside Park/Finchley, it can only be because of the popularity of Sushi (which I do not like). However it serves hot food, which in the past has been great.
On this occasion there were five of us, and we ordered nothing clever from the menu. The staff seemed confused by their own menu and actually one of our party failed initially to get any food despite the fact that the place was not especially busy. My wife and I ordered bento boxes, she having a tempura one, and mine being a grilled salmon and beef mixture. The portions are big, and there was a taster portion of miso soup provided before.
The food arrived only moderately hot, scoring no better than a 7 on the CHOF scale. However the included rice was almost cold. There was absolutely no point in complaining, as clearly these people had lost the plot on the night we visited and our lives are too short to wait for a re-run of preparation.
On previous occasions, we have been awarded a 10% discount (even at weekends) but some weak reason was found why we were not eligible this time.
At 10p.m. without actually saying the words, they were trying to turf us out. They have longer hours on a weekend.
If you are not a drinker, the food is reasonably priced, but when hotness is a factor, then no price is right if the food doesn't meet expectations. Our friend who suggested the visit ( he has a well filled loyalty card) was apologetic, and thought the real staff might have been on holiday.
The morals to this story are that August is a problematic month to eat out in the 'burbs of London, and that consistency of delivered product is what generates loyal customers.