If you go into the distribution database there is a table called MSrepl_commands. This has all the commands that have been and need to be executed on subscribers. You can literally delete whichever commands you don't want!
If you go into the Replication Monitor and navigate your way through to where the error is, it kindly tells us what the error is and also which command it is. The transaction sequence number relates to
MSrepl_commands.xact_seqno and the command id to MSrepl_commands.command_id.
With this, you can create a DELETE statement to get rid of the command and within a minute it had sorted itself out. Obviously I had to rectify the problem with the original script!
This bit of SQL will do it...
DELETE FROM MSrepl_commands WHERE xact_seqno = 0x0002434800000DC8000100000000 AND command_id = 3
Be extra cautious here as deleting the wrong thing could have a catastrophic impact!!!