Rocker cover rivet replacement

[NZmember]

My rocker cover cap is loose when fitted as the rivets that engage the cap thread are worn. Does anyone have advice on replacing these rivets?

[814CWE]

drill em out and use engine tag rivets ,but shorten them a bit before fitting and slightly enlarge holes in rocker cover where the rivets will pass.

looks like the later wingard cap,, as seen floating around at autojumbles or ebay, or as fitted to a lot of minors these dont fit as snug as the proper early mini one either