Looking for Advice

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I'm 24 years old, from Scotland, weighing in at 19 stone 8 or 274lbs and trying to lose weight for health reasons and career choice.

My myfitnesspal plan is to go to the gym 3 times a week for 120 minutes, I can burn off 980-1200 calories a day doing this so far.
My max calories I can have without exercise is 1730.
I use mostly cardio equipment Crosstrainer/Elliptical Trainer, Treadmill, Stationary Bike.
May occasionally break out some kettlebells.

Backround.
Well as a child I had broad shoulders, bit of a belly but nothing much, though at the time I thought i was much larger due to the concerns of my father and also the venemous words of my school class-mates. I have done various exercises such as walking the west highland way a hiking trail in Scotland that goes from Milngavie all the way to Fort William, this made me lose ALOT of weight, though due to my own choices It was steadily regained as I gave no thought whatsoever as to what I was putting into my body leading me to go from a 11-13 stone (154lbs-182lbs) broad shouldered teen into eventually over my own abuse of snack food and energy drinks and other bad dietry decisions lead me to become a 19 stone 8lbs Adult, which leads me to the here and now, were I have realised how bad the situation is, leaving me to not be happy with my body image, even more so than I was as a child. I want to make a change in myself, I want to lose the weight and at the end maintain that healthy weight so I can lead a happier life with a more positive body image and pursue my chosen career hopefully, as well as being able to job or run for a decent amount of time.

So in general I feel like i need help across the board from my exercise routine to my diet, i've previously failed in my efforts to lose weight in the gym, and I do not want to make that mistake again, so this time I am going for re-building my lifestyle from the ground up, focusing on not just how much I exercise but also giving myself a healtheir diet that also tastes good and feels filling.

On the diet side, i'm not a big lover of fruit, vegetables i'm quite fond of broccoli,cauliflower,green beans,carrots,various forms of beans, Red meat intake is not particularly high it's mostly white meats, enjoy porridge and cereals, these however are my good points.

I'm an abuser of habitual eating as well as having a sweet tooth meaning if i'm watching a movie I want something like chocolate, or crisps and many other types of snacks, once I start I don't stop till i've eaten it all, their isn't an off switch to it till it's all gone, which can then give me a taste for more.

Possible things i'd like to know are most likely simple enough.
What are the long term troubles I may come across?
What are the short term troubles I may need to overcome?
Any recommendations of things to try for my diet?
Exercise advice, what would help my metabolism or fat burn?
Should I use weights, do they assist in weight loss?
Is it adviseable to fit in more time in the gym or space it out?
Other weight loss activities good for calorie+fat burn that don't require the gym.
Any less stressful or fun forms of exercises that I can do after/before my gym to enhance my workout?
Was recommended by the gym staff to get a heart rate monitor, is their any cheap/affordable heart rate monitors that do not require a smart phone?

If anyone can help it'd be appreciatted.