Wire Clamp missing on Cooker Spur Box

[Skullkeeper]

So i install white goods for a living and have come across an issue when installing some Electric cookers,

Sometimes when i open the Cooker Spur Box the Cable clamp is missing, i was wondering if there is a universal "plate" or cable clamp that i can buy any where, If i open the Spur and the clamp is missing, my Company policy is to FAIL the installation and advise the Customer to get a new Spur fitted,Hopefully i can get hold of some "Spare" cable clamps
Thanks

 

[FatAlan]

Make a note of the connection unit manufacturers and see if they do spares?

 

[Mike Johnson]

Would it not be just a flat bit of non conductive material and a couple of self tappers?