Mugzy, I was kinda in your situation a couple of times, or more, in my 20's (fucking turbulent time in anyone's life, full of fun, but full of fucking challenging shit too)....
I only got out of those situations by either:
..ending up being such a twat, and in such a mess that I forced myself to "reform" for a while...which is what you seem to be doing...it only ever happened when i got in a real bad way....and never worked properly until I moved onto.....
...the most succesful solution for me was always to make a clean break, whether that involved moving to Poland, hitchhiking home from Turkey, in later years movin to Turkey (where I knew I'd stryggle to get wizz

), fleeing Turkey, just moving cities in UK.....going to Spain.ending up staying in Morocoo by accident for 6 months...I most often ended up drifting into the same company, and the same patterns that I'd been in in the UK, or my hometown, but once I started to see the patterns, asnd realise that eternally moving about wasn't necessarily the best solution, I started to sort things out about myself, for myself, and tried to strike a balance, and prove to myslef that i COULD DO SOMETHING and see it through if I needed to....
Sometimes a clean break, and just taking any fucking job you can makes you focus, then the drugs, and the drugdgery that your drug dependence has become, well, they all start to lose importance....
It helped that I did a TEFL qual very young, and had a fair bit of experience when it came to moving countries, but why not just make a clean break in UK? Or abroad? You're intelligent, you have qualifications I think (I got a couple of jobs abroad with fake documents, only photocopy degree certs etc), the only thing going against you is you look a twat fucked on meph in a jester's hat....
Turn up in a foreign country with your degree certs, a smiling face, and a can do attitude, you'll get a job, and loads of fanny, but hopefully not genital warts
You really sound like you're in the situation, and you are the kind of person, that would benefit from a clean break, maybe a more drastic one than seems possible, but it might just have some results for you.
I made a lot of messes in me 20's despite all the moving about and fornication, but wouldn't change owt...anyone who doesn't struggle with life in their 20's is labouring under false illusions...you realise there's something needs doing, needs to get out of you...do it.
LOL, finished work early, wife and son at home, been down allotment sat in the sun drinking with some neighbours and their kids, hence the rambling on, but it makes sense, to me.
tl,dr