HI, hopefully I have a quick spell 2 handed.
The system is changing (it's always changing, actually!), so I am talking off top of my head, you will need to research on your own.
But roughly:
For staff, you should be able to get CRB checks done via an umbrella group (you do identity checks and form-filling, the umbrella group does quality control and submits to CRB for you). If the staff have never had a CRB check in your setting previously, the check will be free. If they have previous CRBs, you have to pay - -and yes, they cost a lot!!
The umbrella groups include Capita, TMGCRB (google for websites).
For volunteers who haven't been checked in your setting previously, you should also be able to get CRBs done for free via TMG/Capita. £40 is a good price, actually, I thought you'd have to pay more like £55.
Comtee members all CRBd via Ofsted, who also require DC2 for extra background.
I said system is changing... sometime next year (I think) people will start to get individual disclosures, they won't get a CRB check done for each new role or setting. I don't know exactly when that new system is coming in. A person will give you their disclosure number & proof of identity, you will phone to get the info over the phone about that person.
CAT=personal message on MN, use the yellow letter symbol next near my name on this post. Or I can cat you if you don't mind.
I wrote a whole manual for our preschool (which I could forward you), which if you read it might help you get some idea. But the procedure/'best practice' is always changing, so it would only be start.
hth.