In message
,
David writes

Are there any fillers,repair kits etc that can be used to repair the
sink?

Not a sink, but my son managed to crack our cistern, which caused a slow
but annoying leak. I drained the cistern, let it dry, then rubbed
silicone sealant into the cracks, before refilling. That was months
ago, and it has not leaked yet - touch wood!

--
Graeme