The difference is minimal from standard class which already is comfortable and new, first class seats offer a separate cabin with slightly better seats that recline, some with table, and power outlets at the seats for charging and powering mobiles and laptops.Buffet service on-board, though it really is just a trolley selling crisps and snacks, including coffee and drinks such as wine and beer - which is more than adequate for a two hour journey.
The website says you can upgrade on weekends for £5 by paying the ticket collector directly on board, though the benefits don't outweigh the price. A journey of this length is equally achieved in standard class at a third of the price.
Though be warned, there is a ridiculous pricing structure when it comes to British Rail, had I taken the return journey 30 minutes before the price is inflated by about 400% - for the same journey, just different time. Though this is seen in the airline industry, it doesn't make sense on routes as these.
