When I joined, I was promised training and career progression and so far have received none.
The company shouldn't really have been promising you training that appears not to exist. However I think that perhaps your expectations may be a little unrealistic I'm afraid:
My question is, at this stage in my career, I feel like I should be progressing formally instead of just attempting to self-learn and having to bug people for help. Am I over expecting or does my company have a duty to be training me? Or is this 'self-learning on the job' common in Engineering?
Apart from company or regulatory specific things formal training is rare in actual jobs - it's obviously not a universal rule but outside of internship programs most "engineer" type roles (I'm more on the software side myself but the experiences of friends on the electrical side seem similar) but "self-learning on the job" and asking more experienced colleagues for help as needed is far more typical. This isn't an educational environment like college or school - it's a job.
I also feel asking for help alot can annoy people and lowers my value, so I'm becoming more and more reluctant to do it.
You're looking at that wrong - yes there needs to be a level of consideration for the other person's priorities and time when asking for help but people should be expecting a fresh graduate to ask lots and lots of questions. And not asking is actually what is lowering your value - if you don't ask and are unable to find out on your own what to do (or figuring it out yourself takes a disproportionately long time vs asking) then that's just another task/skill you are unable to perform for the company.
Say the company gives a task to reverse the polarity of the widget couplings or something that sounds equally double-dutch to you and you're unwilling to ask for assistance. Then two days later comes to you asking:
Hey sidA30! Have you reversed that polarity yet? We need to ship the widget to the customer and we can't do that until the polarity is right.
you respond with:
No, I don't know how!
I'd be fully expecting them to come back with:
Well why didn't you ask?
Now, see if you can imagine yourself saying "I didn't want to lower my value" as the reason without cringing.
You're clearly a reasonably smart person - they don't give EE degrees just for showing up after all but your employer will have hired you knowing that your knowledge is incomplete and that you'll still be on a steep learning curve. So ask questions, ask for tips on where you can find info yourself and you'll be progressing in no time. But if you want that progression you need to be the driver behind that, a graduate role means the company is there to help you learn not to spoon feed you.