as everyone else has said, replace the idler & tensioner
when my timing belt broke it was waaaaay worse than that inside but it was the tensioner that had died, rebuilt it all with all new bits inc britpart tensioner (Doh) & it lasted 150 miles (muddytruckers 09) before the tensioner was dead again, replaced it with a gen one & all good
if i can find the pic of inside my timing cover i'll post them, was almost a timeline of events i did in 08 with tong clay on top
also id strongly advise replacing the front cover seal as thats where the water n carp gets in even you have the wading plug in