SVP have a cheap dvd writer at the moment - the LiteOn DRW-6S160P DVD+/-R/RW/DL Writer is on special offer at £17.99 including VAT.
Specs and info from the site...
This DRW-6S160P model offers high-speed double-layer DVD write speeds, in addition to top of the range 16x DVD-R and +R writing speeds.
Write Speed: DVD-R: 16x * DVD-RW: 6x * DVD-R DL: 4x * DVD+R: 16x * DVD+RW: 8x * DVD+R DL: 8x * CD-R: 48x * CD-RW: 24x
Read Speed: DVD-ROM: 16x * CD-ROM: 48x * Access Time: * DVD: 160ms * CD: 160ms