Just curious as to what it is as it fell out of the bag when I was filling the tortoise enclosure, it also likes to go into striking possition when you get too close.

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I am not sure, but I have heard similar spiders referred to as "mouse spiders". Harmless UK native spiders, quite fuzzy in appearance - sometimes described as felt like.

You have a young one there by the looks of things. I don't know just now what the species is likely to be, C_strike can probably hazard a better guess than me.

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"All I know is my gut says maybe"

Brachypelma albopilosum (Charlotte)
100's of Harvestmen
Member of the BAS and AAS.

IF it is a mouse spider, it would be a very smooth, and shiny bum, comaparitively thick and stocky build. and as you said, would assume a threat posture as a defense.
As GRB mentioned, it does look immature, which is why is particularly small, generally these get to about 1-1.5cm legspan or so.
Quite common in UK up as north as about Scotland anywho.
They dont web much in the wild as theyr nomadic and move too often to establish a base. In captivity on the otherhand, they often do make their own webs

I keep Scotophaeus blackwalli.

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thanks guys

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