[Closed] Is this fine or have I lost 2 vital washers..?

Off to a trail centre this weekend and I'm using the ST4 for the first time since I changed the bearings.

Where the seat stay meets the chain stay there is a bolt with a allen key on the inside going through the bearings and out the other side to a sort of flat nut which is compatible with an open-ended spanner.

Having put this back together there seems a gap between this flat nut and the bearing - ideal for dirt to get right into the bearing I'd have though. The flat nut has a slightly raised disk in the inside middle which is causing this rather than it not being done up tight enough.

Am I missing two washers - I didn't think so looking at the parts left but it's not impossible.