For around £150, you could kit yourself out with a decent DA machine, pads and polishes, than do it yourself.
You would have to be a complete and utter numpty to do any damage with a DA. It might take a little bit longer to get the results that a pro would with a rotary, but if you take your time, and do a bit at a time, you'll have the satisfaction of knowing you did it yourself. You might even enjoy it.
There will be plenty of guides on forums etc to point you in the right direction. You really can't go wrong.