This snippet of information is not on the HeyPhone web site.
John Rabson can provide a spreadsheet-based component list for the HeyPhone, showing suppliers' order codes, but he warns that it is a draft document that he wrote when building his own Heyphones some time ago. It is based on components available in the UK, at that time, and is not guaranteed to be up-to-date.
For enquiries about the HeyPhone PCBs see http://creg.org.uk/heyphone/contacts.html
where you will also find John Rabson's address.