I just went with that 12vSw from the phone cable. I am assuming that the current drawn by the PS is not going to be that high.
Having done that, and put the PS fluid in the new lines for the first time, I turned the system on for the first time. The steering is soft like butter but then the car is off the ground and has no wheels mounted...!
The PS pump (from MR2 Spyder) does not make any sound! 
Don't know if it is running or is defective! Once I gave a few side to side turns the fluid level did go down. This was expected as the lines were new and the fluid was filling up the spaces. I had to pour 10-20ml of fluid more to bring it to correct level. However until I put the front down with the wheels I won't know if the pump is running and everything is ok...!
Any ideas? Also of the people who have used a MR2 or a similar 12V pump, can someone tell me if they can hear the pump work or feel the vibration if you touch it? This is too silent unlike my GAST brake pump which makes a racket...