Buy the crush washers from a proper bike shop and not Main dealer
or from a main dealer that does proper bike bits and not just manufactures bits.
Once I was desperate for some and I almost told the parts guy(yeah I know not his fault) to 'you know what'. The price was **** take. IIRC it cost more than the sump waher which would make it more than 30p
.
You should be able buy them direct from Hel I think. I tend to buy sort of in bulk.
Cheers
Ben