Also I am now looking at this one (http://www.ebay.co.uk/itm/AC-100-240V-to-DC-12V-Switching-Power-Supply-Regulated-Transformer-for-LED-Light-/230844619265?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item35bf695a01&_uhb=1#ht_3557wt_1037) and it has 2 -v's and 2 +v's is this just so you can easily attach 2 12v devices at the same time?
Thanks!