Sorry, only got a few minutes spare before the computer conks out and can't find the power lead, so won't be a long post, but but but - I'm a lawyer and when we first moved to Bath (8 years ago) I was on mat leave from my job at a City firm. For some mad reason I went back afterwards, and commuted daily for the next 10 months, until going on mat leave with my second child 
It was not particularly fun, but it was do-able - and there were certainly a lot of people whom I saw on the same train day in day out, so clearly not a completely off the wall option. The train is 1.5 hours to Paddington, and the service was averagely reliable. Often fine on the way in and more likely to be delayed on the way home, which was frustrating. If it was going to go wrong, it would generally go wrong around Reading - a lot of work is being done to the railway there, though, which presumably should improve matters.
Coming home, I used to get the 18.00 from Paddington, and it was always a massive scrum for the train, with people literally sprinting down the platform. Larges numbers of people used to get off at Reading, though, so if I ever ended up without a seat, I could usually get one at that point.
So, do-able, but not (in my view) a long-term option - was quite knackering, especially once I'd added on travel to/from the station at either end. It made for a very long day, on top of a very demanding job with long hours (which they wouldn't let me do part-time). Am now a lawyer (part-time!) in Bristol, which is a considerably more civilised environment generally, and a much more palatable commute (10 minutes on train)
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Computer running on empty, HTH. Was actually quite long in the end!