They're six years old and the general recommendation is to replace tyres that have been exposed to UV light for five years or more. No supplier/manufacturer liability under the Limitations Act. I'm currently on Michelin Cross Climate which are all weather tyres but have the added benefits of a better, softer ride and less noise with no detriment to fuel economy. If you can't get the size, then Nokian Weatherproof or Goodyear Vector 4 Seasons.