Hi meabh,

My car's a 4/4 2006 build but I'm sure the p4 relays are in a similar position as mine......
....behind the dash, high up, just left of the steering column when looking forward. Use a mirror to see them. Unless slim wristed and mobile detach the dash to change.

Hope this helps.

Regards

Geof
70th Anniversary 4/4 (Duratec 1.8), model 1995