I consider myself pretty au faix regarding postal and telephone scams and can usually detect them a mile away. However, luckily for me on this occasion, DB answered and put the phone down.
He them came to tell me, where I got a little confused, and went to find out about it on-line. The following links to someone quite savvy who was alerted straight away.
This link is from Staffordshire Trading Standards and is worded a little differently but also has some numbers of use (not always we have found), such as the Telephone Preference Service and Silent Call Guard (not heard of that one).
Basically they telephone and start speaking straight away about your pension and a bonus in the next few weeks of £1000.
WARNING: They don't ask for anyone so anyone who answers will think it is for them.
They then ask you to press 5 or is you have been contacted before, to press 9 to unscribe.
WARNING: This links you to a premium phone line and can quite quickly add up to £100's of pounds on your bill.
If they call again, we thought we might just listen and not push any numbers to see what happens (hopefully it is not a reverse charge call of any kind).