Doubt it, the question is what remedy do you have? Breach of contract is limited to the contract amount itself, and no judge will be insane enough to give you a sizable portion of your ticket price back.
Assuming action is successful you may get like £10 + court costs, but even that I would be skeptical you can get.
If the TOC has laid it on thick about food/drink in 1st class when selling 1st class tickets, I see no reason it wouldn't be successful. However you are right that you wouldn't get much back, especially when the service is typically a bacon roll and hot/soft drinks.
I'm petty enough to pursue a claim for such amounts. I nearly did recently against Just Eat for the sum of around £13 for a pizza which arrived having been carried diagonally by a courier, but they caved after I mentioned I'd file a Money Claim Online claim and gave me a full refund. Problem is, I suspect the operators would do the same, meaning the cases never come to court. This is a favourable outcome for the individual passenger who gets compensated, but unfortunately means the operators/retailers continue to get away with it against 99% of passengers. The only way the operators and retailers will learn is when they're held to account by consumers and consumer rights groups unfortunately.
The amount wouldn't strictly be limited to the contract amount, but to damages. If you happened to get a £9 SeatFrog upgrade but no food/drink on a 5 hour journey normally serving hot food and booze, you could probably claim for more than £9 worth, plus the filing fee. It would be a bit of a trick though as you'd need to show that you ended up spending say £10 on something equivalent at your destination.
I've had a successful civil claim against WizzAir and found the whole process a breeze actually (except the first time I filed I made a typo in their address and thus lost that filing fee as I had to file a new claim).
