No funding then, stops at 25.
First thing is read all the threads on here about why it is not a good idea to try to become a plumber right now & how dangerous it is to sign up with some training providers (who want to take thousand's £ off you) & will tell you it will be alright.
Secondly find an employer who will take you on as trainee then you will need to find a local college who is running plumbing courses for mature students & enrol.
Long & short of it is Donmaxie, you can not learn how to be a plumber by going to a training provider / college, you have to be working at the same time as learning, if you think it is any different then I am sorry but you are mad.