Passenger travelling from Paddington to Chippenham (perhaps a member of this forum) on a service to Penzance planning to change at Westbury for a Transwilts service to Chippenham wishing to upgrade to First class using a Weekend First upgrade.
On a direct train to Chippenham normal cost would be £15 two zones price. Train manager however charged £20 three zone price which Westbury falls into even though the passenger has to travel via Westbury (or Bath, also in zone 3) due to engineering work.
As a matter of principle, I don't thinks passengers should be asked to pay a higher price for travel by a longer route when their regular route and timing is unavailable or impractically bustituted - especially because of rail industry instigated changes such as closure for engineering. We have had some interesting discussions with
GWR▸ (and Transport Focus) on that and largely established the principle. I don't see any reason the same principle should not apply to first class upgrades.