What is this??

[beamout]

Timber frame house - this is the inside wall and DH just saw this! It is grey fluff with white bits in it. House is very old and badly insulated. Worried it is something growing but also we have dogs that shed any many many spiders. Any thoughts?

Woodworm I would think, judging by the holes and the larvae.

Looks like woodworm

Looks like woodworm to me too.

Also think it is woodworm.

Holes are very old and I think must be from a previous infestation. Guess this could be a new one. But the grey fluff is odd! This was over the bed and I am lying here now feeling all itchy

Could the grey fluff be carpet moth larvae perhaps?

Image attached

hard to tell from your pics but stringy fluff can be dry rot (actually a fungus)

I agree with @Pollywoddles , carpet moth.

The woodworm damage is very old, looks to be oak. They'll lay eggs in the sapwood but not the heartwood as it's too hard and eventually disappear (so long as any softwood has been treated).

Thank you - off to investigate dry rot and carpet moths...

Fortunately (?!) we have an active wood infestation in the loft so getting that sorted shortly and will ask them to look at this as well...