Assuming that you want to travel direct via the WCML, the following combination is cheaper.
London Terminals - Milton Keynes C.
Route VIRGIN TRNSONLY Anytime Day Single £4.65 PRIV (for outward)
Milton Keynes C. - London Terminals
Route VIRGIN TRNSONLY Anytime Day Single £4.65 PRIV (for return)
Milton Keynes C. - Rugby
Route Any Permitted Anytime Day Single £3.40 PRIV (for outward)
Rugby - Milton Keynes C.
Route Any Permitted Anytime Day Single £3.40 PRIV (for return)
West Midlands Day Ranger £5.95 PRIV (for outward)
West Midlands Day Ranger £5.95 PRIV (for return)
Stoke-on-Trent - Warrington Stns
Route Via Crewe Anytime Return £4.30 PRIV (cheaper than the ticket from Crewe itself)
Freedom of North West 4-in-8-Days Rover £16.75 PRIV
Lockerbie - Irvine
Route Any Permitted Anytime Return £10.30 PRIV
Total: £59.35
Condition 19(c) of the
NRCoC allows you to take a non-stop WCML service between Euston and Glasgow Central with the above combination as there is one
leisure travel pass in the shape of the Freedom of North West 4-in-8-Days Rover.
There may be other even cheaper options.
Thanks, I'd loved to be proven wrong about PRIV being the cheapest option!
PRIV through fare is very rarely the best value ticket for long-distance intercity travel, thanks to uncontrolled price hikes on SORs over the years by the TOCs.