Not my thing myself but noticed these used to be £29.99 each and are now £19.99. From what I can tell they are single lamps, rather than a pair. The 10% discount brings the total cost down to £35.98 a pair, so I thought they'd be worth a mention. Reserve online to collect in store only.
You would also need a relay, spade connectors, appropriate wire, a battery connector, fuse holder, fuse, and some means of connecting wires - scotchlocks would be the lazy option, or a soldering iron, solder and heatshrink probably the best approach. Or I believe some sort of "fast fit kit" is available from halfords too.
Sold at £45 each here http://www.csmsupplies.co.uk/product.php?productid=16660&cat=289&page=1