Hi, This is for cars up to 1997 Fuse #4 in the fusebox in the engine bay (back left corner as you look into the engine bay, they number from right to left), there is also a relay on the fusebox behind the side trim in the UK drivers footwell, relay #2 top left corner of the panel.
From 1998, Fuse #51 in the fusebox near the UK passenger headlight, bit dificult to give a position without a drawing but there is the main set of fuses then a row of relays and to the right of the relays are six fuses and #51 is the bottom of these and by the side of this fusebox is the glowplug control module.
nigel, October 2010