If I was doing modbluetooth again from scratch, I would have included the service handles in the tuple returned from gatts_register_services, but at the time nothing was using them. (This would be easy to support on btstack too).

See #7675 (comment) -- because this is only to support the database hash functionality, I'd much rather see this supported by the built-in default GATT service, rather than putting the onus on the Python code.

I think it looks like we're already going to have to fork NimBLE for other reasons (e.g. not using a hardcoded IRK, adding support for doing private addressing on older controllers, and some issues around the changes in v1.4), so I guess this would be a good first thing to add to our fork. I notice Espressif have already done the same.

because this is only to support the database hash functionality, I'd much rather see this supported by the built-in default GATT service, rather than putting the onus on the Python code.

This (database hash functionality) is done in C in PR #7877. So this PR is no longer needed and can be closed.