I received a call from Themes Water recently. The numbers they rang me from were +44 800 009 3806, 0800 980 8800, and +44 800 009 3651.

This morning, I received a call from this number. I chose not to pick up since I never respond to unfamiliar numbers.

I'm a bit dubious about this number, to be frank. They claim to represent Vodafone, but I'm not entirely convinced.