Long time lurker here that runs a fitness business.
For the stubborn belly fat that you'd like to lose -
Short HIIT workouts and intense metabolic circuit workouts with weights (depending on experience, don't do these if you don't already have a solid lifting routine in place) are the best route for shifting stubborn fat from my experience. Most people struggle with the last bit of stubborn fat because it gets a bit more complex than just lowering cals/doing more.
You are going to be a bit limited here by how much mass is beneath the fat though. If you're not carrying enough mass you'll end up resembling a skeleton by the time the abs poke through. Did it myself as like most people who started out overweight, abs were the 'end goal', once you get there though there's definitely an element of 'now what?'.
Realistically as well the time frame is a bit short, this shit takes years to figure out what works for you. If you didn't have abs at 11st3 before then you're going to be looking at losing over 2 stone in the space of 4-6 months, possibly more, with this kind of time frame and the amount of weight loss required I would say with complete honesty that there is no healthy way of achieving it.
If you're determined and serious about it is not unachievable at all, a good pt/coach may well be worth investing in to get things going in the right direction as well. Hard work and consistency will get you to where you want to be, it's just a matter of being patient, as I said it takes years to figure it out but it is 100% worth it (45 is just a number too, never too late to start).
Okay,
In short, I am a Yo Yo dieter. Im an all or nothing type of guy. Im not saying that I have been 28 stone, gone down to 10 then back up to 30st. I just tend to lose a lot up to my hols then out it all back on again. I never lose enough to see my abs but can really lose a lot of weight from elsewhere.
At the moment I am about 13st3 or so, but I have been as low as 11st3 one year. I know peoples weight can fluctuate but its a real real effort to lose it again, I mean it takes over my life planning meals etc.... tbh its quite difficult juggling my shifts, family stuff too. I have tried lots of workouts and diets over the years
At the moment I just got back to the gym about a month ago and I have started to see a difference in size already (muscle memory?) I had a break of about 4/5months as I got so pissed off with it.
I do 5 times a week with a workout focused on each boy part each day (Back, Sh, legs, arms, chest) and I do 10mins of HIIT when I feel like it.
I also attend 1 or 2 circuits a week.
My issue is, Im just so tired all the time.
This is likely too much and you'd benefit a bit more from a higher frequency routine that has less weight days. I admire the dedication to be getting yourself down to the gym 7 days a week but I can also guarantee you will burn out quite quickly. It is infinitely better to train twice a week for 52 weeks of the year than 5 times a week for 26 weeks. Consistency and sustainability is the number 1 thing that holds people back as over the course of a few years this is what will give results.
I would look to switching to a upper/lower split that runs over 3-4 weight days per week OR a full body routine 3x/week with a focus on compound movements, this would give faster results to begin with for less time spent. Bro splits do work but personally I've found higher frequency to give better results when drugs aren't involved. The goal here would be to find something sustainable that you can do for a long period of time without burning out.
how old are you btw?
My testosterone is very depleted
Have you had this diagnosed with blood tests? This will seriously work against you and impact quality of life in later years if it is indeed the case. Dieting down to levels of body fat that your body is not comfortable with will lower it further, which is ok if you've got a healthy amount and can afford it to drop a bit, it will make you feel like death if it's already low though. NHS ranges are unfortunately extremely wide and if you test in the bottom of the range they will consider it 'normal', 'normal' being the test levels of an 80 year old man and the symptoms to go with it. If it is low then the tiredness you mention above would very likely be due to this.
http://www.peaktestosterone.com/Symptoms.aspx
Have a read through this and if you are finding you suffer from a lot of the symptoms then go get it checked out. There is a huge difference between having TRT administered by a doctor and taking steroids, same drug but wildly different dosage/goals. There is a huge stigma attached to it because of what it is, but it's no different to women getting exogenous hormones for birth control, essentially medicine to improve quality of life.
If you want more specific advise I'm happy to elaborate on any of the above.