Observation: A lot of poking around on the 'net indicates that "tyre-shopper", the online offshoot of National Tyres, seem to offer the best prices.
This is not an advertisement. If anyone knows a better place, I'd love to hear about it!
I bought Barum Vanis 2 102/100T R rtated tyres at £71.50 each, fitted (at a National fitting centre), including disposal fee and new valves (could have knocked off the disposal & new valves I suppose and saved about £4).
Next I will see how the tyres perform.
I could have has Barum Vanis (not "2") about a tenner each cheaper, but the "2" ones are said to be "fuel saver", and 1%[1] of my 12,000 mile approx annual mileage comes out at about £19 in fuel[2], and the tyres will hopefully last 2 years, so that'll be a saving.
[1] Michelin "energy savers" are supposed to save 1% of fuel costs per corner fitted compared to an "ordinary" non-low-rolling-resistance tyre. I'm assuming Barum Vanis 2 will "save" 0.5% per corner. However, this may be a fallacy.
[2] 12,000 miles at 40MPG (slight optimism, more like 38 with roof rack and My Right Foot), assuming £1.35/litre.