I love M and S non-wired bras after falling out with Gossard wired bras several years ago, as they started to get very uncomfortable. One of the problems I’ve found though is that I find a bra that’s perfect for me, then they stop making it, and the whole process begins again . I looked to see if I could send you a link for the latest two styles that work for me, pretty, good support etc, and just discovered they are no longer available. It’s a good job I bought a few, I do this as I’ve been caught out before! I wonder if your rash could be caused by the silicone that some bras have below the bust to stop movement , this was a problem for me , they are not meant to be worn for a full day. I took them back and got a refund after pointing out info on the label and my allergic reaction. Good luck!