Marshall matrac mh11's
They're a new version of the tyres that came on my k12 4 years ago...in fact 3 of the 4 tyres i changed were the old marshalls ^_^
Online price (asda tyres) £62.34,
called them directly £59.16
...saving £3 per tyre, just from a phone call
The guy did try to get me to go with the matrix(?) ones at first, he had them in stock but they were £65.45 each and rated F for fuel economy and C in the wet. ?.the Marshalls were rated C for both, he just had to order them from a different supplier
Edit:
The Continental one's in that size are about £90-£110 each!
Although I think they have B ratings?
Edit2:
http://www.asdatyres.co.uk/?gclid=CMCX0bzXiLsCFSKWtAodpUwA9w
Continentals ratings for 2 of 4 kinds are worse than the Marshalls.
I guess it just depends how much of a brand you want, I never had a problem with the old Marshalls so sticking with them worked for me