I'm kind of in the same position but with a male, I was recommended to bring his castration forward which I did at 5months rather than 6 and hes still doing it.

I'm considering trying those feliway diffusers, which apparently help, but I am confused about distinguishing between inappropriate wee'ing and actually scent marking, as per the feliway website, the diffuser will only help with marking?

I'm assuming any urinary problems have been ruled out ? which is the other thing I am now considering, but as he was only at vets yesterday and has wet food not dry I would have thought they would have looked into this, as we have told them the problem.

Sorry Ive not been much help, I'm a newbie, but your thread was of interest and I hope you get it sorted, I'm sick of washing pi55y clothes every day

Best wishes