On top of that the warranty won't be valid in Australia and if anything goes wrong you will need to contact Nintendo UK and pay for shipping costs there and back.
To be honest its going to be more hassle then its worth.
Yeah, I've never had any problems with any Nintendo products that required the use of the warranty. Come to think of it, I've never had to utilise a warranty for any electronic devices I've owned.
The UK Wii U basic pack is a good $70 cheaper than the one in Australia. Plus I don't pay VAT so with shipping is basically 199 pounds from Amazon. Sweet deal for me!