There are technical workarounds

Technological workarounds

For those with sufficient technical knowledge it is comparatively simple to install technology such as a VPN or using the TOR network to get around any country based restrictions. In short those would make it look as though someone was accessing a site from a different country. The government’s own (draft) impact assessment recognised that:

“Adults (and some children) may be pushed towards using ToR and related systems to avoid AV where they could be exposed to illegal and extreme material that they otherwise would never have come into contact with.”

See here for details of other things that are wrong with Age Verification