Thank you Maarten!

 For the benefit of "onlookers", here is a small line that you can paste in the script, just under the dropping of the first TRs (CAUTION: this is for ASCENDING SLICES -- see notes):

slicetimer -i ${rest}_dr.nii.gz -o ${rest}_dr -r $TR

in case your TR variable is not set you can also use:
slicetimer -i ${rest}_dr.nii.gz -o ${rest}_dr -r `fslval ${rest}_dr pixdim4`

NOTE:
1. It will overwrite the _dr image, so if for some reason you want to keep that 'original' file, you can set the  output to ${rest}_stc.nii.gz but then remember to change the input to the next 2 steps (i.e., 'de-obliquing' and re-orienting) to ${rest}_stc.nii.gz
2. This command is for ASCENDING slices.
     If you want descending add: --down to the above command
     If you want interleaved add: --odd to the above command (I think..)

Cheers

 Martin