I need to reset call guardian but have forgotten the PIN number to access the system on the handset
Hi @popsycle, welcome to the forum and thanks for posting.
I've had a look at the user guide and around the forum and found this previous thread which the user resolved by resetting the Base station. It may help you resolve this.
Solved: lost pin for call control on BT advanced cordless... - BT Community
Cheers
John