Hi Newton,
Yes, I shouldnt think it's anything to overly worry about. I filled my passport up in two years and when I applied for a new one last year they wanted new photo's. I haven't changed that much in two years but they insisted . . . . . possibly as Morgoth says, they're being a little sensitive over the olympics and stuff and all the attention the UK is receiving?
With all due respect
Regards
Marmite