Nicked it off wikipedia as I'm lazy tonight. Don't judge! Obviously the whole Stacy storyline was different and you could do it differently quite easily. But there's an option to go a similar route.
Gwen blames Spider-Man for his death, which sets their relationship back for a while. Gwen leaves for Europe to cope with her loss. She wants Peter to ask her to marry him and convince her to stay, but his guilt stops him from proposing.[volume & issue needed]
Peter goes to London to see Gwen, but is forced into action as Spider-Man and leaves without seeing Gwen. Gwen eventually realizes her error in trying to pressure Peter into marriage. She returns to New York and they get back together
But with regards to London, isn't it just the working title? London Calling? I'm not sure if there was ever anything concrete about London filming... Yet.