Hi Andy
This sounds strangely familiar

.
I graduated in Ecology in 1997 and have had 10 years "off" and am now half way through an MSc (doing it distance learning which is great as I run a small business I can't quite leave yet). I've being doing as much voluntary work as I can squeeze in, but I'm getting a bit demoralised (to say the least!) as I think my chances of getting a reasonable job after are quite slim - I've just failed even to get an interview for a job that I was
exactly the person for if you read the spec.
I'm a bit limited as I can't move away from the area and jobs are few and far between: I don't mind a bit of competition, but there have to be jobs available to compete for! I also don't think there are very many other sectors where you are expected to have a Masters and two years voluntary experience to get a £16k job!
So, sorry - no practical advice

(other than - sounds like you're going the right way about it...) but will be interested to see what those in the know think!
moo