Looking at your piccies, it looks like the foundations of the pier, along with part of the pavement has dropped and shifted towards what looks like an elephant trap dug out and reinstated by one of the service companies(water, by any chance?) in front of your drive.
If the elephant trap was the result of a water leak, some of the ground may have been washed away from under the pavement and around the pier foundations.
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local