Have removed cover to access 2 securing screws. Both of these removed but there is resistance when I try and wiggle light cluster out. Seeking to replace whole cluster as it is damaged.

Pull harder. The taillight is attached to the body with only two screws. You’ve already removed them.

As @Zelinski said above, keep wiggling.. took me ages as I didn't want to break the pegs and didn't know just which direction to pull them out.

On refitting I lubricated the pegs and grommets with Vaseline to hopefully make the job easier next time.