I picked a full set up last year including valve stem seals & the cam bolt washers Mal is talking about, paid about £50 on eBay from some dealer that was having a clearance sale. Bargain I guess
I see non of the rubber washers genrator cover gaskets are cheap from robinsons. you could get away without one for the ignition side or better just make one out of a cornflake packet, there's no oil behind it.