My understanding is that excessing to change the time a ticket is valid and keeping the same route is supposed to be charged at the full difference of the two tickets. Only route changes should be done at half the difference.
In your case you're actually doing both, so I'm not totally sure where you stand, but you'll probably get them for 50% of the difference.
For a change of route it is charged at half the difference.
If the excess is for the purpose of changing route, then the rules for a change of route excess are what applies,
regardless of whether this also results in a change of ticket type.
Your change of route should be calculated as 50% of the difference between the Off Peak Return that you hold, and the same fare (i.e. Off Peak Return) for your new route.
That's not the rule, which is (from internal KnowledgeBase, aka "iKB") as follows:
- RETURN TICKETS (Change in one direction) - Half the difference between the price already paid and price of the cheapest Return ticket, available for immediate travel that allows the customer to travel on the route and Train Company of their choice.
Back in the days before iKB, "The Manual" used to give an example:
A customer holds an Anytime Single from Hereford to Alton routed “not via London”. The customer wishes to travel via London on a day at a time when a Super Off-Peak Single is valid. If the customer does not wish to break their journey, they should be charged the difference between the fare already paid: Anytime Single (£38.50p) and the Super Off-Peak Single (£43). The Excess fare is £5·50. Note: This example is not necessarily the current fare.
I don't
think that example is currently documented anywhere 'official' anymore, which is a shame, as it avoids any potential for confusion regarding the rules. It's been quoted numerous times on this forum over the years, for example:
Ignoring the fact most stations refuse to do upgrades correctly: If I have an Anytime Return from Taunton to Basingstoke (route Salisbury) and wish to upgrade the return portion to go via Reading on a Sunday when Super Off Peak is valid, is the upgrade as follows: Taunton to Basingstoke (route...
www.railforums.co.uk
Some ticket office staff erroneously claim that the rules do not allow the excess to be to the "cheapest" ticket, and instead claim that it has to be the same ticket type. Also
some ticket office staff erroneously claim the full difference should be charged. But the rules are clear for all to see, and all staff in a position to retail tickets should have access to iKB.
If your original ticket was a Super Off Peak you could also potentially excess it to the more expensive Off Peak, but I don't think you can do the reverse (i.e. a negative excess).
You cannot get a "negative excess" from the point of view that you can't get money back, however that doesn
However, you might have trouble finding someone prepared to issue the excess - several times I have been told that I need to buy a new ticket. I would suggest that you explain what you intend doing at the booking office where you buy your ticket. Turning up at the gate line at Waterloo without a valid ticket could prove "interesting".
Although if the customer boarded at an unstaffed station and there was no opportunity to obtain an excess until then, the passenger cannot be penalised for not having a valid ticket (notwithstanding that route excesses do not incur any penalty for doing so on board).
If you're going to and from different places, as well as by different routes, how does this work? Your returns are from Tonbridge to where? If to Lymington Pier, is the point that Portsmouth Harbour is somehow en route between Lymington and Tonbridge?
The origin and destination must remain the same. Portsmouth Harbour isn't en-route and travel wouldn't normally be via Portsmouth, however interchange within Portsmouth (routeing) Group is permitted, although this validity via Portsmouth Harbour is "for interchange only" so I would advise against attempting to start, finish or break/resume a journey at PMH.
