[frak_your_couch]

First thing that comes to mind is maybe you're underselling your successes in your resume. In particular, if you've been working a long time in the banking sector and you don't mention sufficiently prominently that you have experience outside of that domain, then you could get pigeonholed.

Second would be that there is something about your non-technical skill-set that is sending up red flags. What feedback did google UK give you after the rejection? Was it a bad fit technically or culturally?