If you think that having CCNA after your name is going to get your a 100k a year job (in whatever currency you like) then you're mistaken. Companies aren't just hiring people because they have certificates anymore. It is nice to have so that a prospective employer has an idea that you know some things, but the CCNA level is the most basic Cisco certification, and is close to becoming a "paper cert" in some ways. 1000GBP for 2 years of classes doesn't seem like all that much -- 12 week courses for things here in the US cost that much and those aren't even really good courses; I'm not sure I'd be confident that this class you're taking is going to truly teach you the things you need to know to be competent, rather than just teaching you how to pass the test. (And over the course of 2 years at only 2 nights a week, it'll be pretty damned easy to forget stuff.)
I think you might be better off trying to get a low-paying job in which you might get some experience with networking and Cisco stuff, and then use self-study to polish off the things you didn't learn too much about.
Oh, and I didn't vote because I can't unconditionally choose any of the options. 🙂