We can't answer this for you and really nobody should try since you didn't provide any areas of your life that you find meaning in or industries you'd be interested to work in.
Most jobs out there aren't going to have any meaning and the ones that do wont don't pay as much as you want since you've indicated in other comments that pay is important to you.
Heres what I'll tell you. Accept the fact that most jobs you have and most jobs everyone have are meaningless, put your 30,40,50 hours a week in at your current job and find meaning outside of work and just realize that work is a means to an end.
Or, quit your current job, find something remote realize that you'll probably take a pay cut but with that you might be able to get a reduction in hours that you can spend more time doing what you want and be back in your home town with your family.
Internal transfers are pretty easy too; it's not unheard of to switch teams every 18 months or so, so when you get sick of working on whichever huge distributed system you start with, you can go work on consumer hardware, one of the various operating systems, Google Maps, the Chrome browser, a site like Google Docs, one of the many iOS apps, one of the Cloud products, etc etc.
Working at Google isn't the wonderland some articles paint it to be, but it's definitely not boring, and there are lots of interesting people and projects around. You might not find your job itself to be super meaningful, but being surrounded by thousands of other engineers who all would like some meaning in their lives makes for an interesting community, and tons of fun little at-work side projects.
It seems to me the London location is a constraint not because of your job but because of your partner. So I'm going to play devil's advocate and say that you may as well capitalize on that and get a job that can't be remoted away and get as much out of it as you can before you both decide you've had enough and move away.