Where do you fine folks purchase your replacement bolts from for the rebuilds in our lives? My chassis came with the majority of bolts missing. The standard pitch metrics I can get easily but the fine pitch ones are proving more troublesome...

in most cases eBay is your friend

Your local fasteners should be able to fine a perfect match or as near as for any nut, bolt, rod, washer etc etc  you'll need.
Google search your local area and pop over with whatever it is you need more of 

There is a company on ebay called KAYFAST and they have always been pretty good for me

http://stores.ebay.co.uk/kaysfasteners/

For me it would depend what the bolt was being used for and if a safety critical element I would want to know where it had been made and that it had not been supplied from some questionable source that may have certified it as a grade or quality that it in fact isn't. Things not being what they are described as is becoming very common in my world at the moment....

Been very good to me...

http://www.quality-suppliers.com/

cheers H

http://www.volksbolts.com/

For the hard to get bits

If you want fancy looking things like spike heads, or titanium with loads of finishes etc.

http://www.pro-bolt.com/

I use this guy he has quite much in stock and reasonably priced as we are not buying thousands. http://www.postalparts.co.uk/

I have used my local place for most things but the odd hard to get one ...... try http://www.volksbolts.com/

awesome, cheers for all the replies guys My local place does all the basic stuff and some of the less common but the fine thread metrics in high tensile, not so easy!

Duchy fasteners in perranporth Cornwall. I am local so easy to go in and they always come up trumps . If you know what you want they will post to you. They are so knowledgable and efficient and down right helpful.i have been in numerous times for one or two odd sized bolts and Allen screws and they are always happy to help even with tiny orders . A really excellent business. hIghly reccomended👍