All sorts of organisations conduct surveys for different purposes.
I am not aware of any Wiltshire Council survey using random telephone numbers, but often specialist surveys are undertaken by specialist consultants who might start off saying who they are and who they are doing the work for and then they ask if the person on the phone is happy to answer some questions which will help towards planning things better for the area.
It might be possible that Westbury Town Council has engaged a consultant to undertake some surveys because of the Neighbourhood Plan exercise currently underway.
Retailing surveys do occur every 10 years or so to determine where people do their shopping. This helps to understand what is going on and where more shops need to be planned etc.
I don't think any call is a scam unless they start asking for financial details such as bank name, account number, password or for money to be actually paid or moved.
My elderly mum keeps getting a call that claims to be from Amazon saying that they are confirming that her purchase costing about £75 will arrive soon and they need to confirm the bank details and the credit card used. It has taken me about 6 months of repeated calls then more discussions about the same situation to convince her that it has got nothing to do with me and that she cannot possibly have an Amazon account because she has never used Amazon herself (I have bought stuff for her using my account) and that my account has nothing to do with her. Thank God, she now just puts the phone down as soon as they say it is Amazon. I have now told her to report it to the Police every time it happens again on the Police non-emergency Tel No: 101.
Another regular problem seems to be calls to my Mum claiming to be from Talktalk which start off saying that she has a problem with her broadband and they need some details to fix it. She knows to put the phone down on this one as she is not on broadband ..........
Also, there is another regular scam which seems to be about saying that her PC has a problem that needs fixing and they can talk her through it. She puts the phone down on this - she does not have a PC! Lately, she's been telling me that sometimes she keeps them on the line for ages talking about her non-existent PC and asking them to repeat everything about 10 times and ...
Personally, I stopped answering the land line phone a decade ago and all my calls go to an ansaphone. I rarely return calls unless they are proper calls from someone who at least knows who I am and what I have got a phone for. Calls to my mobile will only be answered if I recognise the number or the phone's address book recognises the caller...
If I get a mobile ansaphone message, I'll return the call only if they say what it is about.
This has saved me from wasting hours every month on nonsense calls from morons and scammers and surveys .... I used to get calls from drunk folk in pubs saying that they have videos of me in the nude (this is definitely untrue) ..... or that they know about the porn on my PC (which is just them guessing and having a joke). I've also had death threats especially from really nasty horrible scousers with disgusting revolting accents ... All that has stopped ....