Thank you all, for the supportive replies, especially Lyn.
I have 'come out ' to my wife about these feelings , and at the moment, she seems to deal with them by blocking it out. As would be expected, initially there was shock, and talk of separation. We are (on the surface at least) more or less back to the asexual affectionate relationship which existed before the surgery. She is not ready to consider counselling or online support, either alone, or as a couple, and has said that I'll have to do it ( dress) at times when she's not around.
There are conflicting drives- Obviously I shouldn't do anything hasty, but the positive surgical margin ( no treatment yet with PSA remaining <0.1) makes me think 'don't put things off'. Yet the requirement before gender reassignment surgery to have lived in the desired role continuously for >1 year is there. It is enough of an emotional limbo to recover from prostate cancer surgery without having to also live in another limbo for a year to address the issue of gender dysphoria which occupies my every waking hour.
But on the latter, I don't want to lose my wife and best friend. That would inevitably happen if I had to live as a woman for a year. So compromise is needed, which I feel would work. Now, if hormone therapy were indicated for cancer recurrence, most men would chose medication to reduce testosterone, as opposed to surgery ( orchidectomy), whereas I would jump at the chance of the latter.
I realise that for many on this forum, even the mere notion of volunteering for castration could seem like madness. Many men are undergoing immense personal struggles on HT. But personally, orchidectomy would alleviate some of the distress I feel in a male body. If I were on HT, my wife would accept this as necessary treatment for cancer, if however, I had a bilateral orchidectomy and cited the reason as gender dysphoria, she would be horrified. It is not that I wish biochemical recurrence, rather that such surgery could allow me to feel more feminine whilst hiding it under the guise of ongoing treatment. The business of taking oestrogen and dressing is another matter.
A bit of a mess. I wonder if anyone on here has begun HT/castration before biochemical recurrence has been demonstrated? I suppose the 'normal' desire to maintain things as they are is uppermost and it doesn't happen. Yet some women chose mastectomy whilst healthy, when family histories suggest high risk...