Darren,
the obvious answer is - this very much depends on what job you are applying for is!
As an employer the only two reasons why I look at person's education is to establish (1) whether the person has at least some background for the job they are applying for (it is often ok if they don't) and (2) whether the education route they've chosen tells me something about their character, e.g. how hard they like to work, how high/low they aim for, etc.
How about you try looking at your choices in a very different way:
1. Forget about what qualification to get to increase the probability of you getting a better-paid job. Instead, figure out what is it you really want to be doing when you are 50 (!) and what source of income you want to pay for your living expenses at this age. This will take you some time to think about, and don't worry, it does not need to be your final choice, you are allowed to change your mind later...
2. Find 3 people you respect who are 50-70 now and currently do what you want to be doing or at least are pretty close to that, your 'role models' if you like.
3. Find everything you can about them. How did they get to be who they are now? What choices they made in their career? What education did they choose? What made them the way they are? Try contacting them and ask for their advice/life story, they might even be willing to meet you or help you in some other way.
4. Then you only have to figure out how are
you going to do the same they did... easy!
Note that this is not going to give you a detailed prescription for what exactly you should do; applying what you have learned to your own situation and planning your moves will be your next task. You will however gain a set of guidelines and very importantly your realisation that you need to keep your (very) long-term perspective in mind when making your day-to-day decisions.
Does this help?
Good luck,
MV