Adafruit Voice Bonnet (ADA4757) noise

Just purchased the voice bonnet, and the seeed wm8960 driven equivalent, just to see which model is the better. Glad I did; the seeed ReSpeaker 2-Mics pHAT is 100% as expected and works well, whilst the adafruit model, despite following their website instructions for installation, works but has an extremely persistent high pitched “clock” noise which I cannot get rid of. The amplitude of this makes the product unusable for my purposes.

Seems as if quite a few folks are having the same issue on the adafruit forum.

I’ve used the product so am not sure how this would work in terms of a return?