I dislike the Tories as much as anyone but I completely disagree with this. Being an MP is a job, like any other, and regardless of party its right that you can claim expenses incurred as part of your job. Perhaps there should be some sensible limits on these, however saying you can only claim for travel and food will absolutely give preferential treatment to southern and London based MP's over northern and Scotland based MPs as no-one is going to travel down to London on a daily basis for a role as important as that, and nor should they. MP expenses are a drop in the ocean, these people run the country. If work said to me I had to be in London for half the year I would absolutely only be doing it if my stay and all expenses were covered. I think the days of duck moats are long behind us and anyone abusing the system gets dragged over the coals now, but being realistic the role of MP has to be an attractive role to people and not paying for travel out of their own pocket. Even I can get first class travel to London for work so someone making key decisions on how the country works I don't begrudge it at all. £5k in energy expenses is basically £1k a year, which is essentially going to be a standard energy bill for 5 years - don't really see the sensationalism in that.
It's stuff like this that keeps positions like MP's available to the working class people rather than it being the joy of people like Rees-Mogg.
Anyway I may be wrong but I believe its only allowed to purchase first class travel if its cost is cheaper than the standard walk on price at the time. We've seen before MP's getting harassed on trains, and regardless of what flag they fly, they probably need to be able to work in peace and quiet.