We moved house recently ~ redirected mail for 3 months. We've since extended it for a further 6, but have now been contacted by a company sending mail to our previous address.

Should I return with "not known at this address" or ignore them? Can a company find out whether you have mail on redirect?

 

Did you leave your new address with the new owners? Do you owe money or something?

 

Nope

and

Can't say

 

Put it this way.... my Dad moved to the Channel Isles and had his mail redirected..... a certain NIP may or may not have been redirected with all the mail and my Dad may or may not have ignored it

He never heard anything back about it, so I would guess that if the police couldn't be bothered to try and find out if the mail was redirected then "a company" wouldn't either.... I suppose it all depends on how badly they want to find you!

 

Police would need a Court order to obtain your redirection info, they would not be told automatically that a redirection existed.
The only time something would not get redirected is if it was a (Housing) benefit letter.