I'm really sorry to say this, but from my own experiences within my own marriage, and the experiences of many others here, it doesn't sound promising for the future of your marriage... irrespective of whether you choose to transition.
A couple of things you've said concern me greatly about your situation:
Quote from: Bob Wascathy on August 11, 2016, 10:51:45 AM
To say she didn't take it well would be an understatement, we had 2 weeks of silence, accusations, recriminations, and ultimately it was made clear to me that my "issue" is Not To Be Spoken Of.
This, and many other things you've said in the thread, is indicative of abusive behaviour. My ex used to do the same to me, torturing me for around 2 weeks at a time with the same 'cold shoulder' behaviour, until eventually I'd capitulate and 'apologise' just so I could get a bit of affection again.
This next bit is also very much part of an emotionally abusive relationship - I suggest you research 'emotional abuse' and see how much of it resonates with you:
Quote from: Bob Wascathy on August 14, 2016, 04:19:19 AM
My needs and wants seem to be subservient to my wife's. I try my damnedest to make her happy, ultimately though my best never seems to be good enough. I'm constantly made to feel selfish for wanting anything for myself... I just don't know what to do.
In a marriage - or any long-term, committed relationship - each partner should be putting their other half's needs above their own. That way, nobody is being selfish and nobody is being neglected. If one of you is putting in the effort but the other one isn't, that doesn't bode well for the future of your marriage. How much longer can you tolerate being neglected? You've put in a good 13-year stint already (and I daresay there were many wonderful times during that period), but if your marriage has come to the point where your wife is being cruel to you, do you honestly think it'll get better and she'll start treating you kindly again? Especially now you've come out to her about your trans feelings. Is she going to accept you warts & all and start loving you again, or is she going to use it as a stick to beat you with every time you have an argument? I don't know either of you from a bar of soap, but I know which way I'd bet on that.
Here's another cause for concern:
Quote from: Bob Wascathy on August 12, 2016, 01:55:41 PM
... since I disclosed my "issue" last year she's become even worse if anything, if she really wants to hurt me she makes comments about me "looking for another woman... or man". As far as she is concerned my "issue" is Not To Be Spoken Of.
Aha! And here's the crux of the entire problem. That 'or man' bit of her jibe is very telling: she appears to be homophobic. And if you transition to a woman and remain married to her, then everyone else will perceive her as being a lesbian... and that thought is repulsive to her. Which could very well explain why she's reacting so viciously: she sees the entire scenario as an attack on her identity as a straight married woman and on her reputation within your community. Oh look, here's yet more evidence of the same:
Quote from: Bob Wascathy on August 12, 2016, 01:55:41 PM
I've tried to tell her but where my wants and needs are concerned she seems to have a kind of selective deafness... attempts are usually greeted with replies such as "I'm not a lesbian" or "do you know how much you've hurt me?"
"Do you know how much you've hurt me?" Because she doesn't want other people to perceive her as being something she despises, and she thinks you're forcing her into a situation she'll find intolerable. I don't know her, but I rather suspect that the foremost thing in her mind is probably: what will everyone say? What will people think of her? Will they mock & ridicule her for being married to a (you know which slur)? Will they subject her to the kind of venom & vitriol she reserves for the LGBT community? It's not about you... it's all about her. Sound familiar?
In her defence, it's also entirely possible that she's simply not attracted to women and she's worried that if you transition she'll no longer be attracted to you. And that is entirely legitimate & valid.
On a slightly different subject:
Quote from: Bob Wascathy on August 13, 2016, 03:39:20 AM
I'm reeling from some pretty personal comments made on another forum, pointing out my personality defects and basically accusing me of time wasting and attention seeking.
In my experience, anyone who tries to call you 'attention seeking' is basically somebody who likes to get all the attention themselves, and feels jealous when somebody comes along with a better, or more deserving, case. For that reason, you can confidently ignore anyone who ever accuses you of being 'attention seeking'.

In conclusion: I believe your wife is probably emotionally (and financially) abusing you. And a lot of abusers tend to ramp up the abuse if they get any hint that their partner is trying to leave them. It's a way of trying to maintain control over their partner: if you feel confident enough to leave, then she loses her 'cash cow', her comfortable life and her status in the community. So it's possible that she's trying to even further diminish your self-confidence to make it difficult for you to leave, so you can keep supporting her.
I notice you're in the UK (me too!) so I can assure you that courts in the UK don't routinely stop access or custody for parents just because we're trans. Your wife might want to you think they do - and I'm willing to bet the farm that she'll try to use your daughter as a weapon with which to manipulate you - but that's just another way of her trying to frighten you into not leaving (and not transitioning). I recommend you find an LGBT-friendly solicitor in your area and investigate your options - even if you decide not to take it anywhere. Because your wife might initiate proceedings at any time, and if she does it'll help you enormously to have your ducks in a row.
It is absolutely not guaranteed that your wife will get sole (or even any) custody, and who knows? your daughter may prefer to live with you anyway. At her age, if you were to divorce then the court will take her wishes into account when sorting out her custody arrangements. And there's an LGBT Centre in your local area: why not drop in for a chat? They may have some good advice from local people who've been through similar.
All is not lost. You can still be free. And you can still maintain a relationship with your daughter. She's at a great age if you choose to come out to her: if you wait until her teens she may become moody or resentful, so really the best time to come out to her is now. And that might knock some of the wind out of your wife's sails.

You deserve far better than this. We all do.