I found this for you from a question in May 2005
PUSH the grey valve button IN...then press ignighter 3 or 4 times to generate a spark....when you see pilot then KEEP HOLDING IN GREY BUTTON for 10sec....let out slowly...BINGO!
http://cgi.www.a1-gas.co.uk/cgi-bin/www.a1-gas.co.uk/bbmat.cgi?getsubject=2947&script=question&frames=N
Peccavi, December 2008