Question: After graduating from university in the UK, I have heard multiple careers advisors say that it is inadvisable to leave your first career role before you have gained at least two years experience.

However I feel my current role is currently holding back my career progress as I am unable to properly learn industry standard technologies, and is affecting my health due to unbearable amount of stress caused by poor management.

I have worked nearly a year and a half at this company but it is still my first career job. Will this look bad to future employers? I work in a sector that currently has lots of job opportunities.

Answer: 
There are no true "rules" when it comes to jobs and job hunting. I left my first job out of school almost exactly 6 months after starting.

I felt the same as you. My position was very unfulfilling, involved managing the maintenance of equipment built before I was born. If felt that if I stayed, it would impact my future career prospects.

I ended up changing jobs and my career has not suffered at all. I even left the company I moved too after only 2 1/2 years, which led to a series of company/title changes due to my company constantly getting bought and sold (2 sales in 5+ years I was there). After 5 years in the same role though, I interviewed with a massive corporation that has very strict hiring policies, and I got the position. So despite the job/companies changes after 8 years of my career, I have not had any issues, nor have I ever been asked "why did you leave you first job after 6 months".

In short, frequently changing jobs can be a red flag, it usually will not be an issue if you show that you do not make a habit of it. Leaving 1 job (even if it is your first) after 18 months is not a significant problem, but if you change every job after 18 months, it could be an issue later in your career.
If someone is willing to offer you a better job, then you should take it. However, you need to make sure your next position is better.

> 
> unable to properly learn industry standard technologies,
> 
> 
> 

Be a little more diligent during the interview process and ask questions not just about what they use, but why they use it. Do they offer training? What processes to they use and how will you know if they really follow them? Are there good mentors?

> 
> and is affecting my health due to unbearable amount of stress caused
>  by poor management.
> 
> 
> 

This is going to be difficult to make sure your next job doesn't have poor management or something else you're not able to cope with. Maybe there are some telltale signs you've discovered in this job that you can recognize in the next. 

You should consider networking with other developers in your area and get some inside information on how various companies and teams operate. You may find that most have problems in one form or another, so why hinder your career by leaving a job too soon only to take another one that is just as bad.