I'm trying to get a masters to improve my job prospects, i've been unemployed since graduating and my husband has had enough so muh so we're using our savings to pay for my education.
Are there any science sectors which have low competition and burgeoning job openings? Not physics or Engineering related subjects as my specialisms are geoscience and biochemistry.

I wish. My impression is if its not a fashionable area (e.g. low competition) then the funding is not as great (e.g. low job openings).

I agree with coastie. Science is mostly badly paid (for the amount you do) and well paid is competitive, therefore you need to do something that you enjoy or at least can put up with happily.

I suggest moving out of science if jobs are a problem.

Can you get some proper careers advice from your former or nearest university? A masters is a big investment in your situation. There are masters and similar geared towards particular professions that you might consider - a university careers officer should be able to advise you on the options.

Check out the hydrogeology MSc at Leeds and Birmingham. There are more job offers than graduates at the minute, mostly in the field of contaminated land rather than goundwater modelling etc. Starting pay with an MSc is from £22,000 to £25,000 and that's withut any relevant work experience.