Just called me too. Claiming to be doing an opinion poll.

Repeated calling

this number called me twice in two days. Left me a voicemail the first time that consisted of someone repeatedly slurping a drink, typing and then coughing before hanging up. Classy.

This number is a foreign (i.e. outside the UK) call centre shared by multiple dodgy sales or debt collection companies.

These calls without any 0 appearing in your caller ID are almost always foreign call centres.

Best advice for any calls received in the UK without the 0 at the start of the number is to ignore it and not pickup.

If you have a call blocker unit just add the number to it's internal database.