They have two branches here in Coventry and I went to the one in Gosford Street, near Coventry University.
Found out that the "Buy one tyre, get one free" offer is not available for my car tyre size. I only had one replaced - a Barum Bravuris tyre (195 / 50 R 15 82V) costing £45/
It's not that bad considering that I had one tyre changed at the "New Cheap Tyres" shop on Stoney Stanton road. It cost the same for a no-brand Chinese made tyre (the cheapest according to them).
Coming back to the National tyres shop, I wanted to take advantage of their Wheel alignment offer - only £11 according to the coupon. However, when I asked the guy in charge, he said that it will cost me £15. Of course, it's a difference of only £4/ but I do feel like he was trying to take advantage. Another thing that reinforced this suspicion was when he told me that the 2 rear tyres needed to be changed as well. It's obvious I am a foreigner here, but I am not stupid. They still have good thread depths. The minimum legal thread depth is 1.6 mm in the UK while on the tyres on my car, they are between 2.5 to 3mm.
the only positive thing I can say is that the whole process of changing to the new tyres was that I didn't have to wait too long and it was relatively fast. I also got Tesco clubcard points.
That's another shop I won't be going back to. I am not so sure about their other branch at Spon End.