There are a few bits of background work that need completing before a new site can be built - some depend what type of build is involved, yours sounds like a street-furniture monopole-type site. Those will have particular dependencies for a power and comms connection, which may require a full or part road closure. Physically landing a monopole will almost certainly require a road closure - these can all be monitored using the roadworks.org website which is very likely your best bet for having an idea when installation could be proceeding.
In the meantime, it's worth noting this won't be just a 5G-specific install but a multi-technology site. 2G & 4G technologies are provided from all (but the most remote) EE sites, with 5G being an additional capacity provision on most urban sites.
