Yup, I'd advise not using more than twice a day, with several hours in between uses. Kratom has a short half life so if you wait to come down between doses, you're won't develop a physical dependence as quickly as if you were to redose before it wears off completely or right after it does. The amount isn't the issue (1g is a very conservative dose and it's awesome that it works for you!) but rather the fact that with constant redosing, you're not giving your brain enough time to restore equilibrium and tolerance will develop quickly as a result. Everyone is different so that still doesn't guarantee that you won't develop a physical dependence but at least it reduces the risk, and also that way if you do happen to become physically dependent, you'll notice right away and you can stop before the withdrawals get bad. I personally used kratom 3-6x a week, usually once a day but sometimes twice, for over a month and I never experienced withdrawals. I also used higher doses though, so I think at just 1g you should be ok for daily use as long as you're not redosing throughout the day. Kratom extracts are another story though, stay away from those. The withdrawals are brutal. And yeah as far as strains go, there's so much variation it's hard to suggest one, but one thing that is very important is finding a good vendor. We can't discuss that much here unfortunately, but there are plenty of kratom forums that exist specifically for that reason and it shouldn't take long to find a good one.
As far as other supplements/herbal remedies-I don't have a ton of experience with them but I've always liked 5htp for a mood boost, especially after withdrawing from opiates and having to deal with PAWS, so I'd imagine it could help with your situation too. Do a lot of research first if you take any other medications as it does interact with a good number of drugs. Kava tea is also nice if you're looking for something more sedating, I don't know if it's available in the UK but here in the US we have a brand called yogi tea-they make one blend with kava extract and not only is it effective but it tastes pretty good too, and is available at most grocery stores. By the way, congrats on kicking the booze!!