I did a 2 year college course then an NVQ(working for free for someone in my spare time) over about a year many moons ago. While I was learning I used to price jobs for tools, first rad swap I did paid for a bender, first outside tap paid for the 18mm / 300mm masonry bit, first tap change paid for the tap spanners etc...
By the time I was going it alone I had most of the stuff I needed, year 1 and 2 were dire, I barely made a penny, it has been very slowly picking up from there to a point where it is finally paying my bills and I have a little left over at the end of the week.
My advice is to do similar and keep the 10k in the bank because you will need it to put food on the table for your young uns, getting a part time job and working round that while you're building trade up would also be advisable.
Too many people think that all they have to do is get a level 2 certificate and then they have a license to print money, even though the papers tell you that is the case, it is not.
You'll have days where you go to change a TRV and think it will take minutes only to find you're there all day and didn't even quote the customer enough to buy your supper on the way home without making a loss, with time you'll get better at quoting and faster at plumbing but it won't come fast enough if you're banking on instant success.
You will have bad knees and a bad back in 10 years time, your hands will be unrecognisable after the first year, you will go off sweetcorn after your first drains job, you will on occasion get splattered with poop and moving other peoples pubes so you can work will become common place, but it might, just might work out for you, and if you get good enough and busy enough to do it you might make a decent living from plumbing.
I have seen 4 people out of the 20 or so guys who did the plumbing course at the same time as me, none of them are currently plumbers except me and to be honest I sometimes wish I'd chosen the plasteres course, or the sparkys course all those years ago.
Good luck pal, you will probably need it.