[Koha] How to delete a record after entering a rare unicode character

[Marc Nürnberger]

Dear List,

On koha 3.0.3 we edited a title of a record, inserting the following 
unicode charachter 𡼱 [it's a rare Chinese character][Decimal: 139057; 
UTF-8: F0 A1 BC B1] from unicode.org. In the input field it looked 
just fine. But after saving the record, we got a fatal error message 
and the record became inaccesible. Under the old title it is still 
searchable (intranet and OPAC), but if you follow the respective 
links, you get invariably the following error messages:

########

Intranet: Error 404

########

OPAC: The following fatal error has occurred:

Can't call method "clone" on an undefined value at 
/usr/share/koha/lib/C4/XSLT.pm line 56.

#########

Has anyone experienced similar things? Are there any restrictions on 
the unicode rage for input that we should be aware of?

And last but not least, how can I delete or access the compromised 
record again?

Any help would be warmly appreciated.

Best regards,
Marc