I plan to finish laying my garage block footing trench blocks today and I need to incorporate a gap for the entry of services. These services are:   Mains water. Mains electric in a conduit. Telephone & ethernet cat-6 cables. Central vacumn system pipe (provision just in case I fit one with the main unit in the garage).   The gap will be in the first course above the poured concrete to ensure the services are at regulation depth and the course above