yep drilled out and then tap the remaining part of the rivet out using hammer!
 
hmm that was an interesting day, spent ages trying to get rivets out, drilling worked a bit but had to pry the front of the rivets off!Then realised need and adapter for the speakers i have got as the standard ones have that plastic bit on them. So was a complete waste of time. At least I know how to take the doorcars off properly now!
Anyone know if i can buy adapters?
 
yep there is a good set for the mk 4 on ebay i fitted them with maxcars1 to his car very good and fit perfect! just look on ebay at ibiza speakers adaptors!