The prices are bonkers. I have tried drilling out a coin of the right thickness to bodge a washer, pending receipt of the hidden bolt I need. If it works I'll let you know, it's a 10 euro cent coin I think is the right thickness.
I did a bit more digging, I believe this is the part number 'FC-RE105 Chainring Spacer' and its 3.7mm thick. I can't find anywhere that I can buy just the spacer but called my LBS and he said to pop down as they might have something that will fit. Fingers crossed!
The prices are bonkers. I have tried drilling out a coin of the right thickness to bodge a washer, pending receipt of the hidden bolt I need. If it works I'll let you know, it's a 10 euro cent coin I think is the right thickness.