How rude 😁
Some good posts in this thread and I don't really have much to add except emphasizing what Mick said. How much your travelling expenses are isn't really their problem, they are running a business afterall.
£120 per day doesn't sound that bad for someone with 3 months experience to be honest, I certainly know of plenty other trainees (thats what you are despite having all the tickets) getting less.
At this point the bottom line should be how you feel you are progressing in the company on a technical level rather than financial. If you are cut out for work it won't be long till you are out freelancing on your own earning £200 a day, or even running your own gig and sending your own teams out.
Don't forget, the company you are working for know this. If they have been in business for any amount of time then they will have had numerous employees who they trained up who ultimately left them to earn more elsewhere.