Do you have any direct experience of BRC (or equivalent)?
Last time I hired a QA manager, I definitely wanted someone who had at least some experience of BRC, as otherwise it becomes difficult to delegate enough work to make my life as technical manager feasible without working 7 days weeks.
It sounds like you have a good range of experience with food in general, so based on what you've said so far you'd be a very appealing candidate for a QA role, albeit perhaps not direct into management. Again given what you've said about your background, you should progress from there fairly quickly up towards QA manager type roles once you've got a bit more direct experience under your belt. If you'd rather aim directly for management-level roles, I'd suggest targeting smaller companies, as the bigger ones probably won't even bother to consider you unless you tick whatever predetermined boxes they've set. (Your CV probably wouldn't have made it onto my desk for the QA manager position - whether that's right is another question, but it's one of the unfortunate realities of trying to recruit when agents throw large numbers of CVs at you...)
In terms of courses:
1) Call your local Environmental Health Department. They may well offer classroom-based courses in some relevant areas, at a vastly lower price than the commercial training providers.
2) If a candidate had taken online courses then I'd certainly appreciate that this was a very positive sign, and would save me some money (I potentially don't then have to use my training budget on these ). What I would say is shop around and check what each course/provider actually gives you at the end of it - many of these offer an online "exam" at the end of the course, but some will also send a proper exam paper for you to complete and return, and this gets you a proper accredited certificate. There may be a small surcharge for this, but it is the option that you want to take wherever you can.
You may need to have a chat with them about how this will work in practice, as they're generally set up on the expectation that you're already employed and your boss or similar can act as invigilator while you sit the exam.
In terms of the types of courses:
HACCP - doesn't need to be Level 4 (although looks good if you do have it!), so if you can save yourself a bit of time/money by doing so then Level 3 is reasonable.
Auditing - Value is limited without experience, but an introductory internal auditing course is still a good idea, IMO.
Food Hygiene - you may well have it already, but if not then do Level 3 / Level 4. (This is definitely one to check with your local EHO - several run subsidised courses).
What's your educational background? I place a high value on people who've got a decent grasp of basic biology/chemistry, so if you don't have much in this area then you could check out some of the bigger labs and training providers, as many run "microbiology for food" type courses that will at least give you a demonstrable starting point there. The relevance of chemistry will depend on which area(s) of the industry you're looking at, but IMO all QA people should have some level of understanding of microbiology.
Hope that doesn't all sound too negative; just my experiences of hiring people. Depending on the level you're going in at, you may effectively be competing with relatively recent graduates and the experience you have so far should therefore stand you in fairly good stead.
Hope that doesn't all sound too negative