Will I fail a skills test for doing a constant-aspect climb-out? The climb-out for one of the runways at my local aerodrome is over a residential area, with fields to the left. My instructor has had a bee in his bonnet lately about engine failure after take-off if the take-off run is longer than it should be (e.g. after a touch-and-go). He's started encouraging all of us to perform constant-aspect climb-out into the circuit, where we start the turn onto the crosswind leg at the aerodrome boundary regardless of height, and keep the runway end at the same declination in our field of view as the turn progresses. This means we point towards the fields much earlier on, but it hurts the climb performance to do it.

Although I can see the wisdom of being ready for EFATO, I'm concerned about practising a non-standard circuit which contravenes the Noise Abatement Procedure. (The NAP forbids turns below 500 ft, although it is overridden by measures to ensure flight safety.) When I come to do my PPL skills test, would this unusual circuit be acceptable, or will I have to fly a standard circuit with a straight climb-out, turning onto base at 500 ft? I'm in the UK and studying towards an EASA PPL(A).
I fly in the UK, and while there is certainly a "standard circuit" (ie pattern) in the syllabus there are many, many fields that have a non-standard circuit for one reason or another. This is often to avoid antagonizing unfriendly neighbors. 

There's also the fact that the NAP is not a rule or regulation, it's more how the airfield management would like you to fly. 

I personally don't like the constant aspect climb-out idea at all, it will mean you are paying more attention to aspect than airspeed and looking out for other traffic. It also means that the pattern traffic is not predictable for other visiting your airfield or by others in the pattern. So I would push back on your instructor on this. 

As for whether you will fail your skills test if you do it would depend on the examiner's view, and what they are looking for. While a constant aspect departure shows skill, I personally would take a dim view of people doing it despite the published departure procedure, even if it is non-binding. I would discuss it with your examiner ahead of time, and practice your circuits how they say they want it, or at least discuss it with them on the day.