Smash Hits gave away another badge in the issue 16th October 29th October 1980 which was fixed to the front cover.  These were either

 

The Undertones

The Pretenders

Madness

Stiff Little Fingers

Elvis Costello

 

To get the rest of the set you needed to send in 3 tokens, an envelope with Stamps to the value of 12 pence then you too would be the envy of your friends