I though I would share this easy solution for a phone holder.
Basically bought a cheap (like 3 pounds) universal phone holder, meant for air vents on ebay.
I removed the air vent clip part, there was a small screw holding it on. drilled a small hole in the ashtray and used the same screw to attached the holder. I added a bit of epoxy to hold it secure.
I put a strip of double sided padded tape on the back of the ashtray to hold it firmly and stop it vibrating.