Cooks Granny Spacers

[South Bound]

OK folks, can't find anything doing a search and a couple of US suppliers have responded with nonsence, but can anyone tell me the correct spacers I need to fit my granny ring to a set of Cooks CBR Cranks (the ones in my gallery!). Think they are around 7-8mm, but that can make a lot of difference when shifting so want to get it right. Also, any ideas where to get them from? Cheers

 

[cce]

charlie the bike monger (ebay) does all sorts of spacers

 

[stevet1]

Billys also have spacers, but no idea what size you need.