Great Western Coffee Shop

Here's an interesting one:

5th November (2021)
- up to London Standard class for an arrival in the Victoria Area by 10:30
- return first class at around 16:30 (purpose of class change to use 1st class lounge as return time very unsure)
- Senior railcard holder
- Travelling from either Melksham or Westbury

Standard  / First mix is a masters degree question and I only have a batchelors in rail fares!

Day trip I presume?

Most obvious answer is a Standard Anytime Return then an Excess Fare to 1st Class for the return portion.

That's going to be eye-wateringly expensive though and I guess Advance Purchase is out of the question due to the unknown return time. Unless the person travelling picks a late enough service that they are guaranteed to be able to catch and then just twiddles their thumbs at Paddington until departure time. I can recommend the food in the Mad Bishop and Bear. Alternatively they can kick back and relax in the First Class lounge.

Is the person travelling confident in using esoteric but perfectly valid tickets? If so there maybe options...

Maybe split tickets at RDG & buy a 1st day return from/to there only? Must be cheaper than upgrading the whole return journey?

Yes, he is ... need to be written up though ...

I will probably press him towards standard class and finding somewhere else to pass time awaiting a train rather than the first class lounge

There are far better, and cheaper nearby options than the 1st class lounge at Paddington, I've always found it pretty underwhelming and it's certainly not worth an eye wateringly expensive fare to which BNM alludes, and I wouldn't question his knowledge of fares!

If money isn't too much of an object why not nip into the Paddington Hilton and sit in the bar with a drink and a sandwich - it'd probably work out cheaper than spending a large amount of money on a 1st class ticket just to sit in the lounge?

Potential cheapest...

Melksham to Didcot Anytime Day Single £19.10 taking the 0751 from Melksham, change at Swindon onto the
0910 to Paddington. Around an hour wait at Swindon. Arrive Paddington 1009.

(Underground journey time to Victoria is around 15 minutes. Tight for an exact 1030 arrival into Victoria after including walks to District/Circle platforms at Paddington and walk to destination in Victoria area. Is 1030 at final destination absolute latest arrival? If so I'll look at other options).

Didcot to Swanley 1st Class Off Peak Day Return. Valid for arrival into Paddington after 1000. £36.40.

Didcot to Melksham Super Off Peak Single £9.75

This combination of tickets allows return at any time from Paddington provided one takes a train to Swindon that calls at Didcot. GWR staff at Paddington should be well versed by now in the 'C4' restriction code attached to Didcot to Swanley 1st Class Off Peak Day Return.

Total £65.25 with SNR Railcard. Plus Oyster fares on underground.

EDIT: Oh, and remember to move out of 1st Class at Didcot!
.

Doesn't a Didcot to Swanley have a Maltese  cross, allowing a underground between London Terminals such as Paddington to Victoria (where expresses leave for Swanley)

It does indeed! I missed that. No tube fares needed.

My original questioner, reading here as a guest, has asked me to express his admiration and pass on a huge "Thank You" to BNM.  He happened on other errands yesterday by a real (staffed) ticket office, checked his needs with the clerk there, and is ready to go.

... and has let me know that the day and tickets worked a treat.   His biggest problem then being how to pay for parking at the station with cash, because there's a coin stuck in the slot ...