Essex_Lad, youll probably need to get your head unit out.
I think the rivet, if i remember right, is behind the heater controls or there abouts.
Basically, just take your time.
Why not do what i did, and spray the main part of the dash whilst in the car? It mightve taken me 2 hours to mask it up ready, but it turned out great. Have to have quite a good spraying technique though, otherwise itll run easily.
Only reason i decided to take it out after, so was that i could fully remove my old, non-functioning alarm.