OK. I'm not letting this go without a fight. Following advice from the legend that is the @Dood I have now purchased some 8 X AA holders. And yes I have now spent more than another Harley Benton recheargable power supply would have cost. And they have two outlets, and phone charging, and they're smaller, and they have a torch.
But where's the fun in being sensible?
Here's the problem though. When I plug in my recheargable batteries I am getting just over 10.3 volts. I read somewhere that pedals will cope with 10% more than the recommended 9v. I don't know if I believe that enough to hook up several hundred pounds worth of noise machines to my non money saving crackpot homemade idea. What can ya'll tell me about this? I mean, other than go buy a proper supply, I've done that they're £35 and utterly brilliant. Does the danger of the output diminish the more pedals you hook up? Should I just throw in one older crappy battery to drop the v's?