Manual or machine? I tried to hire one from HSS, Speedy, Brandon etc but it was difficult to get them to tie down a date. Ended up buying a two tine hollow aerator from Amazon that came with spare tines. Worked a treat, managed to do my lawn (maybe 8M by 25M) in just over an hour. The plugs popped out the aerator with ease and it handled the buried stones without problem (I found the 4 tine models kept hitting stone and didn't get to the required depth).
Jardineer Lawn Core Aerator, Hollow Tine Aerator with Spare Tines, Grass Aerator Garden with Non-Clog Slot, Manual Lawn Aerator for Compact Lawn Soil
https://amzn.eu/d/h3DyrJO