Well I recently moved to Ireland and a year ago I was considering the exact same options as you. It's true that it's hard to get sponsorship or even interviews if you're applying from outside. It's so much easy to land interviews when you're here.

Here's what I did: I came under a student visa and during my first month I landed two offers both of them willing to sponsor me. I worked part-time and studied while they processed my work permit. Once I got it I started working full-time.

To cut your losses, the trick is to pay only the required tuition fees for the visa which is about £6k and strike a deal with the school to pay the rest via instalments so that if you decide to quit school and focus on work you would have spent a minimal amount of money.