Found it on eBay. Still in stock. There are a few stores sell this clock in Australia http://www.livingstyles.com.au/NeXtime-Testpage-Round-Dome-Wall-Clock/69352/ https://www.ohclocks.com.au/products/nextime-testpage-glass-dome-wall-clock-35cm

take this photo to second hand furniture/kitchen stores and contact P&O

Sarah Sarah is right. You won't find a perfect match unless you find new old stock for sale on ebay or gumtree - but you have to be lottery lucky. Try moving tiles from under the fridge, or under the dishwasher, or under the bottom shelf of the pantry. However you will probably break about half of them in the removal process. Don't even bother to try and trim different tiles like annb1997 has suggested as there are too many variables with thickness, finish, texture, colour and gloss level. A mismatched tile will be obvious every time you walk into the kitchen and be a permanent annoyance. Best of luck, Dr Retro of Dr Retro House Calls

Karen Wynne lwynne809@gmail.com 0438340219