Slow start up iMac Monterey SED_CORE Overiding init

Hi,

I have an Imac Retina 5K 27" 2020 running Monterey 12.7.5

It has become very slow booting up.

The progress bar moves for about 1min20secs and then stops for 3 minutes.

When it does boot the Bluetooth devices do not work for several minutes.

I booted it in Verbose mode and the statement

SED_CORE: init : Overiding init

is repeated continually hundreds of times.

The system.log extract is below. It stops between 15:27 and 15:31 with lots of ASL messages before.

Any ideas please?

May 16 15:27:44 localhost syslogd[149]: Configuration Notice:

ASL Module "com.apple.cdscheduler" claims selected messages.

ASL Module "com.apple.authd" sharing output destination "/var/log/asl" with ASL Module "com.apple.asl".

Output parameters from ASL Module "com.apple.asl" override any specified in ASL Module "com.apple.authd".

Output parameters from ASL Module "com.apple.asl" override any specified in ASL Module "com.apple.authd".

ASL Module "com.apple.performance" claims selected messages.

ASL Module "com.apple.iokit.power" claims selected messages.

ASL Module "com.apple.contacts.ContactsAutocomplete" claims selected messages.

ASL Module "com.apple.mkb" sharing output destination "/private/var/log/keybagd.log" with ASL Module "com.apple.mkb.internal".

Output parameters from ASL Module "com.apple.mkb.internal" override any specified in ASL Module "com.apple.mkb".

ASL Module "com.apple.mkb" claims selected messages.

ASL Module "com.apple.MessageTracer" claims selected messages.

May 16 15:27:44 localhost Installer Progress[146]: Progress UI App Starting

May 16 15:27:44 localhost syslogd[149]: ASL Sender Statistics

May 16 15:31:45 10-0-0-103 Installer Progress[146]: 1 Boot windows acquired