I travelled in 1st on the 1336 from York as far as Birmingham recently; the host was great and explained all the options available (many previous hosts have not mentioned sandwiches as being an option), and I was able to have a tuna sandwich and flapjack, as well as a hot drink. I was also offered crisps, but politely declined as I felt that was enough.
The only downside was there was only one offering (of food + drinks) for the entire journey; in the past I've had a couple of drinks offerings. I am sure that if I'd approached the host and asked, I could have had another if I really wanted, but I didn't bother. In hindsight, I should have asked for a bottle of water at the outset (seeing the water fountain at New Street when I changed to my onward train made me think of that; I often bring a bottle with me but failed to do so, on this occasion)
Standard class was full and standing on my train (as you'd expect on the 'core' XC network, at a popular but "off peak" time of day), however 1st wasn't quite full, and in any case I had managed to reserve an individual seat, so was able to get some work done on the laptop unimpeded.
1st class on Voyagers is
much nicer than Standard class, and the seats are much more comfortable than the seats on 80x units used by various other operators, in my opinion.
I was on an Edinburgh to Derby service and the man with the trolley wheeled it through 1st to the galley/TM area then started serving people in 1st from a tray. I asked about sandwiches as I'd seen some on the trolley when he first went past. He said he didn't have any left (so I assumed someone else in 1st had just had them), so we only got crisps and a cake. After he served everyone, he wheeled the trolley back through to standard with the sandwiches still visible! I asked after him but he ignored me and continued on! He didn't come through again so that was all we had from Edinburgh to Derby!
In this case, my suggestion would be to purchase the sandwich and submit the receipt for reimbursement.
I would also ask if it was possible for the receipt to be marked as "first class sandwich unavailable" as evidence, but I strongly suspect that such a request would be denied!