Yep, personally I would get them changed elsewhere, I have always been able to get tyre garages to match online prices, like black circles or equivalent (though they seem to have gone up in price a lot recently...).
I had some Eagle F1 tyres previously, which perished before they wore the tread down, I know a couple of others who the same thing happened, not sure what causes it though.
Should be lasting a bit more than 12k in an Up! though, I think a set of Pirelli P Zeros on my chavvy Corsa lasted just under 18k, though that tended to be driven 'enthusiastically'.
Edited by: Ed!