Pre-new year start, First time MFP'er 70lb goal

Hey,

(sorry, longgggg first post)

I'm here to shift some weight - and more importantly to keep it shifted once its gone! I have tried to join a couple of different fitness/weightloss communities in the past but never seem to manage to fit in, I'm hoping MFP will be different

I figure a good place to start is to explain where I'm at, and a bit history. I don't really talk about my weight, so getting it down might even prove therapeutic?

I'm Male, 26, and 6ft 0in, and currently 21st 11lbs. My current goal is to lose 70lbs by my birthday, 34 weeks away, which will drop me to the 17st mark. Once I've hit target (and I WILL hit target) I'll reassess and figure out what I want to do from there.

I've been in and out of the gym over the last 5 years, and am reasonably fit for my size... At my biggest I was 23st 3lbs, and my smallest (after attempting loss) 19st 6lbs..

I enjoy jogging (treadmill, else my poor ankles/knees suffer), and rowing, and even took part in a 5km charity assault course from hell back in March/April this year - and even completed with a semi reasonable time.

I tried Keto with some success earlier in the year, but really struggle with odd diets, as eating so separately from the family really isn't practical. I've had some health issues over the last few months (indirectly related to weight, nothing major) and as a result (excuse) everything I dropped from that has piled back on (sigh.)

I know, for fact, that when I work out at the gym 4 times a week, my weight is at worst stable, and usually drops without any change to my diet. The problem I have is that the gym is easy to skip after a crappy day at work, and I often find myself needlessly filling my face with chocolate, biscuits, etc in the evenings - for no real reason.
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So, what's my master plan? Well, back to basics I guess. I'm starting before new year, because this isn't just another new year resolution. If I'm not mistaken, 2lbs a week average loss over the next 8-9 months is entirely achievable - I think previous goals have been unrealistic, resulting in failure and then resignation.

I plan on using Insanity from get-go (I did the fitness test this evening, and plan on starting the first workout in the morning). with the gym as a filler where insanity @ home is not an option (I really don't want to home-workout with guests in the house!) I'm also going to do my best to pack a lunch for work and keep a food diary with a calorie goal - which should help me against the vending machine daemons @ the office.

I think I've got everything sussed this time around, but given my track record, I'm here to take as much good advice as I can possibly find. From reading some other peoples posts around here, I really hope MFP can be that little extra piece of motivation that keeps me going this time around...