HIBen
ex RN here, started plumbing in my 40s now 56 and knees failed, wrist broken and back beggared. Be very aware the short course will teach you the same as a 4 year college course, but without the ability or time to get practical experience. A 6 week placement, if it happens and lots never do wont give you a lot, so what small or large plumbing firm will want to take you on?
I did 4 years day release at college, so around 100 days training and exams so a bit more than your course but the benefit of time to put things into practice and I did that through running a property development/renovation business for myself. then I also had some rents coming in to allow me to build my customer base. No one would have taken me on locally, so my only choice was to get out there on my own, plumbing initially, then gas, followed by oil and lpg. Specializing in AGAs and rayburns was another string to my bow. So now net some £50k plus after parts/appliances removed but before fuel, and other costs. Live happily on that myself but costs of van tools etc isnt cheap.
the fact your about to be an ex cabbage head gives you a great work ethos discipline etc, but that wont get you a job, folks want experience, knowledge and skill to make you worthwhile to them. You would be best to hit BG to see if they would train you up for free. I wouldnt bother with brick layer but I wsould look at airconditioning, as my cousin is now sitting pretty on millions as he got in there as computers needed cooling, and still do.
You can probably get into plumbing if your determined but just be aware we need more kit and tools than any other trade and everything about our choice of work seems to cost more than everyone elses