"Mizter T" wrote
I shall have to try buying one for myself from an LU station then. Unless
I've gone mad the price of the Railcard-discounted Day Travelcards I've
bought from NR stations lately has been £5.00. I can't think why LU would
charge a different price! (Unless LU round things down, and NR rounds them
up - but that doesn't make any sense as two-thirds of £7.50 - the full
price of a z1-6 Day Travelcard - is bang on £5.00.) The strange mysteries
of ticketing...

The railcard discount is 34%, i.e. slightly more than one-third, so the
rounding up/down theory *may* be correct. I have a feeling that the
£4.90/£5.00 discrepancy between LU and "NR" has been mentioned before on
uk.r or utl, but I could be wrong. You are right that (at least some)
National Rail stations charge £5.00; I haven't bought one from LU recently.