@23adeline thanks heaps for your help, I had an appointment and the new SA I met was amazing and agreed that it was a manufacturing fault with my strap! Honestly I was all ready to whip this pF thread out with the photos you shared in case they needed convincing like the initial SA! Am so glad they were understanding. Complimentary replacement has been ordered, and I get to keep using my current strap- initially we thought they'd have to take the strap away, then the SA said it's okay, I can still use, even if the cracks worsen I will still receive the new strap.
Really happy with the outcome