I do not know who the lender is - otherwise, I would contact them direct.
From brief research that I did, I saw that "most" lenders would insist that a guarantor would have to have sought independent legal advice before they could be accepted as a guarantor but this didn't always apply for all lenders.
The borrower is himself a IFA, thus, I am suspicious that he may know which lenders would be prudent on who they would accept as a guarantor and who wouldn't be.
But in answer to your initial question, no, I did not have any contact with the lender before nor since signing the document. As I say, I am just worried that someone may hold my details but I don't know who and if I am merely held as a witness or as a guarantor.
Yes, the borrow explicitly said that he wanted me to be a witness, he claimed that he wanted to borrow an additional funds against his property. I was never asked to be a guarantor and was never asked about my own finances as to whether I could be in a position to act as a potential guarantor.
So do you think I have genuinely anything to worry about? And is there a way to find out if any lenders hold my details as a guarantor? If I am held as a guarantor and I was duped, could I still be held responsible for taking this guy at his word?