PIP Independent survey?

Hi, my partner is in receipt of PIP and is over pension age. Today he received a letter asking if he would like to take part in a survey by phone or letter. It said if he took part he would be paid the sum of £10? Has anyone else had one of these and as it is voluntary would it be advisable to do this? Any thoughts and feedback welcome

I am writing further to my query regarding independent surveys for people on PIP. My partner has received a reminder about this from a company called Verian called "Areas of extra cost survey" in the form of an online questionnaire. I would like to warn others who may receive a similar request. I suspect it may be a sneaky way to check up on peoples costs through an independent agency. I hope this might help others. It is voluntary but intrusive, be wary of these surveys. Sounds like it may be an information gathering tactic by the DWP. It offers a £10 voucher for an incentive.!