I presume you mean the Dimplex Cheriton, model CHT20?
1.Remove the top coals.
2. Remove the two screws (one either side in the brass grate at the front).
3. Lift the whole grate/fuel effect assembly upwards to disengage it and set aside.
4. Pull the flame effect rotisserie off the the motor shaft (rubber coupling).
The bulbs are now accessible.
Lee, March 2009