Help with a disk and a No5

Hey team, sorry for the lack of attendance, been a tad busy, finally back at work and am having a ball, had missed locking up bad buggers! But they are stories for another day!

I managed find some great new additions to the collection yesterday, transit chests, wooden ammo box's some tools, canvas covers, a few butts and a No5!

Can someone have a look and tell me what the tool is for!, also the disk on the butt and finally the marking on the No5.

The marking on the No5 is a U94 with an electro stencilled T5906 either under or over it, the bolt has the same U94 as does the barrel, its just ive not seen this before and thought i would ask cleverer minds!

The gentleman i acquire the rifle and "stuff" from is a top bloke and is ex NZDF and now works overseas destroying and making mines / IED's etc safe, he recognised part of the butt marking as a term he uses in his trade and wondered if i could find out for him.

RAF - Uxbridge

see the following link http://www.subbrit.org.uk/rsg/sites/u/uxbridge/

Your not going to believe this, but somewhere in the dim dark recess's of my mind was the word uxbridge, i even said it to dave when i first saw the disk, but he went down the RAF route of a bomb clearing unit? Its good to know regardless. Thanks for that. I will email him the link as well.

Found out what the tools is a: PLUGS, BELT, M.G., MK. 1 - With wood handle; for belts of Vickers .303-in. M.G.