Replicator 2 Spool Spacer - for MakerBot 900gm Spools

UPDATED VERSION: Includes tabs to lock in place

MakerBot has moved to supplying 900gm filament spools that runs against the wiring loom coming up the centre back of the Replicator 2. This isn't a big issue but it does add drag and skews the spool.
This spacer drops into the standard Replicator 2 spool holder to space the 900gm spools back to overcome this issue so it spins freely and stays straight.