The new 29s have a couple of tables on the top deck (and wifi and charging sockets). As Norman says, I wouldn't have thought there was massive difference in time taken. It depends on how long you had to wait at SL.
You didn't say there was a time element, I thought we were just talking...
Even better would have been to pick up the 29 bus from Churchill Sq: it takes you all the way to TW and there are stunning views of the Sussex countryside along the way. I've caught that bus many times, taking kids to rugby matches and it's a constant treat (and only £4.90 there and back too).