Oliver, I've had a series of spider dreams, starting off with very fearful experiences, moving towards lessening fear, through to the spider turning into a cuddly toy, almost kitten-like.

In this one, this line in my original post hints at a possible source of the negative entity/thoughtform/fear/whatever it is -
"It seems to be someone's pet, but that fact, or who the owner is, is never clarified.There are a couple of friends lying in a bed, aware of the spider too, but unconcerned about it's existence."
The couple lying in bed. The phrase "you've made your bed now lie in it" sprang to mind.

Then this section -
"At some point i leave the room for a while, and when i return, the room has changed. The beds have all been made. Someone has been in and tidied the whole place.
We (me and an unseen companion) begin to search the room, wondering where the spider is, a little concerned that whoever cleaned the room has killed it, not knowing it was in there.
The thought of the spider having been killed both excites me and worries me.
I fear for it's life. It is a being and so i wish it no harm, yet would be happy to know that it no longer existed.

As we look under covers for it, i spot what looks like a couple of it's legs, but upon closer inspection find a bag with black rope ties which looked like the legs."
The problem has been cleared up, and then we see that what we're looking at is/was nothing but baggage.