Hi burnstsienna,
Congratulations on your new mattress! :cheer: You certainly chose something using high quality materials.
I have to admit this part made me curious, as mattress manufacturers are required to pass 16 CFR 1632 and 1633, unless you have a prescription from a health care professional that would allow the manufacturer to skip using some sort of FR barrier. Passing these tests doesn’t necessitate the use of flame retardant chemicals. Many manufacturers use a thin “sock” comprised of inherently fire resistant fabrics that encloses the inner foam layers. There was no information on the Seattle Mattress (or Mulligan’s) web site that described how they meet these guidelines, but I suspect it might be the FR sock. Regardless, it piqued my curiosity.
Regarding the specific type of wool mattress protector you’re trying to find, that combination is more commonly found as a mattress cover versus a protector, as I think you’re already realized. Magpie did have a good suggestion (thanks magpie!) for the St. Dormeir – that is probably the most popular one referenced on this forum. Other items that I found after a brief search that are “close” to what you specified that you may also wish to consider are the myPad; CozyPure has a few options that don’t contain wool; suitesleep has one with wool but the cover doesn’t look as flexible as you would like. There is more about mattress protectors in post #89 here. There is a listing of many businesses who deal with wool toppers (I know not exactly what you are looking for but still a good resource) in post #3 here.
One other note. Do not assume that adding any sort of wool mattress pad/protector to your existing mattress will cause that mattress to pass 16 CFR 1632 and 1633. Meeting those guidelines are done on a completed mattress and certified after passing using only the exact combination of padding materials present in any specific mattress.
Phoenix