At least when I worked in the dealers, bike manufacturers would have tyres made to a price and the tyre manufacturers would change compounds or tread patterns of a current tyre model and sell it to be used only for factory fitment and you can't get it other than on a new bike.
PITA but likely still the same. I never understood the rationale behind it, maybe to sell a pair when the first rear wore out?
I too would say the Trailmax Meridian would seem to be an alternative.
Cambrian Tyres in Aberystwyth typically only deal with the trade, but will take a call from the public and give genuine advice.
they are likely your best bet for an alternative tyre.
