You should be able to simply do this:
#if eth0_opts == "bond0"
....
#end if
#if eth1_opts == "bond0"
....
#end if
etc.
Just make every check it's own if/end if, and don't use #else.
Also, you may want to consider changing this to a for loop, as it would
things less redundant.
thanks - making these individual if's did it, but i think its pretty
messy but does the job for now!