Hi Charlotte and welcome!
Swampcollie has it spot on with his post. About 60-70% of the goldens being DNA tested are coming back as either carriers or affected, so it's very widespread in the breed. It is, according to Optigen's website, as prevalent there as it is here. Other websites say the form found in the UK lines is more severe than that found here, but I don't know that to be true. Also, the form found in goldens overall is not as bad as that found in other breeds.
We do have a DNA test for it now, so hopefully breeders will be selective and not breed carrier x carrier, or carrier x affected, and certainly not affected x affected.
There are no new treatments that I know of. Since it appears to be a lipid disorder, there is anecdotal evidence that fish oil is helpful.
My Toby had ichthyosis, but we never knew it. The vet just thought it was puppy dandruff or allergies. Then it went away for quite a few years, and came back when he was much older and under stress from other physical ailments. That appears to be the general pattern of ichthyosis.
And no one here would EVER suggest you give back, or euthanize, your dog because of Icthyosis. In the "great cosmic scheme of things", it's pretty mild compared to a lot of the other things that goldens are prone to.
Looking forward to pictures of your boy!
Icthyosis is likely as wide spread on that side of the pond as it is here. Most Veterinarians just dismiss it as puppy dander or mild allergies and leave it at that unless it's a severe case. A large portion of the gene pool is involved (affected or carriers), so this is something that has likely been with the breed from the beginning. It is nice to now have the genetic test available, so the disease can be bred out over time.
CH Rosewood Little Giant VCD3 UDX VER RA TDX MHU SH MXP MJP MFP T2BP DJ VCX WCX CCA CGC FFX-OG (born 3-10-2007), also UCH HR UH UUD NN UJJ URO1 UHIT a.k.a. "Tito" (the Tito Monster)
waiting at the bridge:
My first dog, and my most special girl
Gibson's Golden Girl, CD, CGC, TDI ( 3-20-1997 - 11-22-2013) a.k.a. "Tiny", "Queen B"
and my heart dog
Gibson's Golden Guy, CD, CGC, TDI ( 01-31-1998 - 01-02-2012) a.k.a. "Toby", "HRH"