Changing locations to get clean is called "pulling a geographic" by the 12-step folks (at least those I was hanging out with). Obviously getting away from bad influences helps.
Glib suggestion: perhaps replacing that addiction with the addiction of exercise might be worth exploring?
Hm, makes sense. I think hobbies in general can be used to take the place of an addiction. I should probably cycle to work more, though ;)
However one of the major problems with heroin addiction is the actuall process of quitting. You can't keep a job during withdrawl, i.e. cold turkey. There are clinics that offer 'five day detox' under sedation, but that's expensive (GBP 5K plus) and good luck getting NHS or health insurance to pay. They offer naltrexone implants, which prevent opiates from working altogether, which removes the option of relapse completely...
Getting a methadone prescription in the UK is also tedious to say the least - you are supervised when taking your daily dose, must report for 'assessment' regularly and so on, which is hard to fit in to a working schedule. And forget about getting enough to take away with you on a business trip for a couple of weeks. I generally have to purchase on the black market when required, which is ridiculous. I'd love to be able to ask my GP for help, and simply be given a repeat prescription for a week or two's supply to take home, but that's never going to happen because they're afraid of it being sold. So I have to buy it from others, which doesn't make sense...?!
There are options aside from Methadone. I've had experience with this in my family as well. To me soboxone looks like a miracle drug. It gave me my friend back.
There are much better options in the UK. I have been attending an evening clinic once a month for the past couple of years where I'm given 2 x two-week prescriptions for buprenorphine which are dispensed by a pharmacy once a week. When I first attended I had to collect the prescription every day - which I did after work - but after a month or so they trusted me enough to move to once-a-month. It doesn't affect my job as it's all done in the evening and the only time I had to visit during the day was my first session there where I met with a doctor to assess my condition and that was a saturday.
I've also been on holiday a number of times and they provide enough to cover me while I'm away as long as I give them 2-weeks notice and provide proof of the holiday and it's duration.
I have been slowly reducing my daily dose and I'm now close to stopping entirely and it's been totally painless. The staff are always friendly and I can't express how much they've changed my life.
But there's no point in quitting if you don't have a plan for how to live your life not addicted. Fill it up with good stuff and drain out the pus of emotional pain that put you there in the first place. Good luck!
Glib suggestion: perhaps replacing that addiction with the addiction of exercise might be worth exploring?