[Toa Circuit]

Depending on what you have available, you _could_ use a three-phase AC motor with a starter.
I'm not sure of the cost, but I'm sure there is a threshold at which the extra cost of that would outweigh the cost of the needed DC converter (Reason #1 why we don't have DC motors on our farm, only AC)... and that for 15 pounds, you are much under that threshold.

I've hiijacked a UPS as a highish-amp testing DC power supply right now. You could do something simalar: just wire into the battery of it to power a CIM, so you have a high amount of juice in reserve but it is constantly recharging- this would work if you don't need continuous use. You wouldn't need to use a UPS; a simple battery charger should work.

For control of DC you should be able to do something as simple as the pseudo H-bridge in a Spike Relay... And with two or one switch instead of relays and signals.