Well Lewy, all is not lost. It isn't unusual for 18 year olds to be penniless. I know I was at that age.

If you can convince a company that you're keen and trustworthy they may invest in you. God knows there seems to be shortage of young people who seriously want to do hard work on the railway.
Freightliner doesn't have
maintenance depots in your part of the world, but it does have terminals at Ipswich & Felixstowe. There are such things as travelling fitters, who work from home and have their own van.
Additionally a company might put you in lodgings whilst you train. If you're prepared to live away from home for a while (and it can be fun

) then that might be an opening for you. Since there always seems to be a shortage of engineers, they may consider relocating you.
You really should get in touch with NXEA. If I have my geography right they are your local operator. If you could secure an apprentiship with them to work on passenger units you can always transfer to a FOC later and your skills would still be relevant (even locos have electric motors nowadays). It's ALWAYS worth getting your foot in the door in the rail industry, insiders usually get first news of the new jobs.
Also as has been suggested here, if nothing turns up immediately, do some voluntary work. Then when you get an interview you may find yourself comparing experiences of vintage traction with the engineer on the panel. Employers DO appreciate it when candidates have got stuck in. (I went to an interview once and when the Driver Manager saw what I'd been up to we spent 10 minutes laughing about how crap Networkers are - He'd been on the commissioning panel)
I firmly believe that if you're young and enthusiastic you'll make it. It may not happen overnight, but persistence wins the day. You want to do a job where there is a shortage of manpower, so at least the odds are on your side.
Good Luck,
FP