Please consult the list of Parcelforce prohibited and restricted goods to ensure that your parcel content complies to Parcelforce regulations.
Go to https://www.parcelforce.com/help-and-advice/sending/prohibitions-and-restrictions
Please consult the list of Royal Mail prohibited and restricted goods to ensure that your parcel content complies to Royal Mail regulations-
https://personal.help.royalmail.com/app/answers/detail/a_id/96