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

Yes. http://www.repairproducts.co.uk/page33.htm. Or Google for sink repair
kit. These kits can be used to repair chipped porcelain, but there isn't
much you can do with hairline cracks. Alternatively, white sealant can be
used as a temporary repair for chipped white porcelain.