Does anyone know how you can get any parts for a Pro-ac speaker ?

I assume you already tried to contact The Sound Organisation in Dallas TX. ?

Griffin Audio in Montreal may be able to help too if you cant get a hold of the folks in Dallas.

I'd be making the long distance phone call direct to England and eliminate the incompetence.  You'd think a ProAc dealer would be able to source them without difficulty.  

Not sure what ProAcs you own but these pegs look almost identical to the pegs on my Response 2.5’s. I measured the  ball diameter on my pair and its 0.225 in. The ball diameter of the peg I linked to below is .just 005 in. larger. They Might work, I’m unsure of the other measurements but at 41 cents each I’d buy a couple just to try.

https://www.madisoundspeakerstore.com/grill-fasteners/peglock-grill-fastener-peg-and-socket/

Sorry, I forgot you mentioned the Madisound pegs already.

The pegs in the link below should work, I measured mine with my digital caliper and found the shank from the flange to the ball tip to be 16 mm long and the ball 5.70 mm in diameter as opposed to 6 mm in the pegs I linked to but I suspect they have compressed the .3 mm over the years.

There are detailed dimensions in the item description.

http://m.ebay.ca/itm/NEW-20-Pairs-Ball-and-Socket-Type-Grill-Guides-Pegs-Plastic-Screws-Speaker-Part...

Yes, let me know please,  I cringe every time I remove the grills,  it would be nice to know I can get proper replacements.