I've been working as a graphic designer for the past six years but my current job requires me to jump into digital design here and there so I'm looking at brushing up my HTML and probably picking up CSS properly etc. I'm noticing lots of resources around to learn these languages, but as far as I'm concerned these are but a means to an end - a site's code can be clean and beautifully written and yet the design of the site could be useless from a visual communication or UX point of view IMO.
I know I'm never going to make a good developer as I drag my heels over learning to code, but my eyes light up as soon as you talk about usability, responsiveness and accessibility. Can anyone suggest sites/places I could check out that are understandable for a basic coder; resources that help me develop my design skills for the digital space at the same time as I improve my technical coding ability?
I'm not sure that I quite understand your question. Do you want to learn HTML and CSS (a necessity today) or do you only want to focus on design? There are plenty of ways (and jobs, if that's what you're interested in) to do that.
To get started, I would recommend just going through sitepoint's HTML reference. I would recommend starting with HTML Basic Concepts (bottom left of the reference) and then reading through the HTML Elements section. Hopefully you'll find it interesting.
In terms of design, your graphic design training will help you with that. I recommend the book The Principles of Beautiful Web Design by Jason Beaird (Sorry about the underlining for you MLA7 buffs). It's a fantastic book that will get you started. You can get it from Sitepoint or, and this is better in my opinion, just check it out from your local library. Hopefully, they'll have it.
After that, use the forums! They're great for any problems that you run into.
Finally, build a website. Not with a WYSIWYG editor, but with hardcore, HTML markup. I'll let you look up WYSIWYG, if you don't know anything about it.
Good luck! Feel free to PM me or any of the staff (I sure hope they'll let you pm them) if you want any help. I'd be happy to talk to you in more depth (digitally, that is).