Wow you have pretty much summed me up atm!!

I will eat so well during the day, go home, touch a small portion of carbs and then boom, three days worth of getting every piece of bread, cheezel and corn chips into my mouth that I can.

And then I can't understand why I still gain weight.

Are you on Metformin? I find that helps me heaps with staying regular. Makes a huge difference.

I have been trying to only eat carbs in front of people, that way I'm more conscious of the quantity that I'm consuming.

PCOS is horrible. My sister and I exercise the same (potentially me a bit harder) and eat relatively the same (she drinks more alcohol) and yet whilst she loses weight, I'm happy/lucky if I can drop 100g in a month.

Slow and steady though right??

If you have gluten or wheat intolerance, then it's imperative that you skip the wheat. You're doing yourself actual damage that will do you more harm than good in the long run. The fact that you talk about "diving into Pandora's box" reinforces the issues you have with wheat.

You might want to check out the Paleo/Primal way of eating. There are a couple of detox/reset/challenge diets (Whole 30 is the big one, but Mark Sisson of Primal Blueprint has a 21 day challenge, too) that is useful for breaking habits and forming new ones. Generally speaking, it's a whole foods based, low sugar/GI dietary framework. Even if you decide not to follow it completely, there are tons of great recipes that are wheat-free by default, and there are a lot of other good resources about things like gut health support, which would probably be useful for you.

Grains aren't the only carb source, remember. So many people forget that you can get tons of carbs from fruits and vegetables. Trade the pasta for spaghetti squash for a huge boost in nutrients and fiber (for fewer calories, too, so you can spend them on a good sauce).

I'm not a fan of planned cheats, but I also consider my choices as part of my lifestyle, so I don't sweat it when I'm not 100% perfect with my goals. That said, I still try to avoid grains, and in some areas, it has gotten to be second nature (burgers, for example, I don't even consider a bread bun and go straight for bunless or lettuce bun without even thinking). It takes time to get to that point, but once you get there, life gets a lot easier. Even if you "cheat," though, it would probably be good to take on this mantra -- "never cheat with wheat." Besides, a good artisan ice cream is infinitely better than a cookie or cinnamon roll.

As for the constipation, make sure you're replacing your carb calories with fat and not protein (if you're reducing your carbs when you try to go wheat-free, which it sounds like, but your diary is closed). A lot of people, when they cut out grains or carbs, are still stuck in the "low-fat" mindset. This is a recipe for failure, because the body literally cannot survive on protein alone with few to no carbs or fat. Fat is essential to human health. I cannot stress this enough, and you can probably find many a novella by me in these forums about the virtues of fats, including saturated fats. Yes, saturated fats are good for us (arguably on par with monounsaturated fats, in fact). Coconut oil, specifically, has been shown to improve blood glucose control, and butter has lots of vitamin A (in the form we can directly use) and vitamin K2, a vitamin that has been shown to be hugely important in overall health. The only unconditionally bad fat is artificial trans fat (hydrogenated oils). Everything else has its place.

Monounsaturated fats (olive, avocado, etc) are great for salads and other cold or low-heat uses (heating breaks down a lot of the other compounds that make these fats awesome, though the fats themselves are fairly heat tolerant). Saturated fats are great for cooking, sauteing, etc., because they're heat-stable (they don't break down when heated). (Fun fact - animal fats actually aren't all saturated, in fact, only about half of the fat from animal fats are saturated, the rest are monounsaturated and some polyunsaturated fats.) Polyunsaturated fats should be used sparingly and only for cold uses, shouldn't be heated at all, and should be obtained from whole food or cold-pressed sources, ideally from fish or nuts. Seed and vegetable oils are usually refined and come from GMO crops, and they're rancid before they even hit the store shelves, because they're high in Omega-6 fats, which are extremely heat-sensitive (and break down and oxidize when heated, which is bad). Nuts and seeds are generally high in Omega-6 fats, while fish (particularly cold water fish), flax, and eggs are high in Omega-3 fats. Try to favor Omega-3 fats when you can, as the two types compete for absorption/use in the body, and the ideal ratio is 1:1 (otherwise, the issues with Omega-6 start outweighing its benefits), but Omega-6 sources tend to have crazy high ratios (20:1 or even as much as 20,000:1), if they include Omega-3 fats at all.

Okay, I've done enough of my infomercial pitch (seriously, I feel like a broken record sometimes), so I'll stop. Hope this helps, though.