are you also applying for jobs direct with the employers and not just through agencies? I have always found recruitment agenscies to be more of a hindrance than a help in finding a job as they only put forward some candidates and not everyone suitable (they always have an idea of who THEY think would be appropriate).
Also, having now been on the recruiting side of the fence, i have used agencies once or twice to find staff, and have always been dissatisfied with the candidates put forward as what they may consider suitable doesn't always match what I consider suitable!. we have now stopped using agencies and advertise in the national press instead.
when applying for jobs, try not to disclose your age either through employment history, or through education dates (unless specifically asked).
also, have you thought about applying for jobs in a different sector (where you could apply your transferable skills such as project / people / budgetary management) as other sectors may be less 'cut throat'?
good luck with your searching and I hope you find something soon.