Biscuit or Furniture beetle

Hi,

I live in the UK and recently we've moved into a new house. in one room on the carpet we've been finding the attached beetles most are dead but some are moving around without an obvious point they come from. We've found about 20 or so and are wondering if they are biscuit beetles or furniture beetle. 99% of the time they are on the carpet and we've pulled back the carpet with no obvious signs they've burrowed through to the carpet (if they are furniture beetles they burrowed through MDF flooring, underlay and carpet to get on top or come from the loft but with no obvious way of getting to this room).
I do have a video of one we caught in a pot (from my sons bug kit).


Link to images
Any help would be wonderful.