Is this genuine or a scam?

Has anybody in my area received a visit from a group offering to assess your house for free loft insulation? I ask because yesterday I had a visit from a young woman who flashed a cxard and appeared to be official. Not being up to date on what's happening in the area I took her as genuine and showed her the attic to assess since we have no insulation up there, upon which she declared that she couldn't assess because there was no access beneath the floorboards. I felt a hint of suspicion and showed her out.

Is the group she belonged to genuine or is this some scam?

I know I was foolishly stupid to let her into my home without a proper search of her credentials so I can do without 'silly old woman comments.' I just want to know if the call was genuine or do I report to the police there is such a fraudulent scam group operating in the area. Thank in advance for any help on this. P.S. Is loft insulation EVER laid under floorboards where there is electrical wiring?