This is the Edinburgh call centre for Ipsos MORI. They are a legit market research company after I researched their number. However, It looks like they treat their staff like utter XXXXX: https://www. XXXXX. Com/r/Edinburgh/comments/9whe32/ipsos_mori_call_centre_in_leith/ I refused to answer any of their questions based on this when they called back.
The line also had a delayed echo tone, which indicates it was being trafficked through an Indian call centre. Do not believe this is any poll caller, this is a scammer trying different tricks, BT should be ashamed for allowing these calls to ex-directory private phone numbers too.