Rail Transport - How Much Should I Plan to Spend on London Commute M-F?

Have your real office in your home.  Seriously!  That is the way it's done here.

Have a look at Regus.  Virtual office space.  Perfect for your situation.  Seriously, just go to the City on Thursdays.  You'll network like a mad (wo)man.

I love Regus! I'm actually sitting in a Regus office as I type . Looks like they have space in the Gherkin. Fun!

As for the working from home thing, I did that for two years out here. It was nice, but it was also difficult because "home life" and "work-life" slowly merged together. I consider myself a disciplined person, but it's just so easy to stay in your pajamas all day and forget to socialize with the outside world. I like the separation that comes from physically leaving the house every day, driving to an office, and having to look somewhat presentable. Keeps me in groove!

I’d think that if you work from home most days and commute into the city occasionally to make contacts, that might be a pretty good balance.  Especially if you do the commute at off peak times then you will certainly get a seat and not be crowded. 

Another thing I hesitate to mention because it sounds like your job and you probably know more about it than me, but you should be aware that British people, especially those in the city, don’t do much small talk and certainly  not about work.  In America I am always struck by people just walking up to you and saying anything.  Then you talk work and then network.  That’s not my experience here.  I’m sure you’ll work that out though.