Hi,
Did you try adjusting the mesh. -
Loosen the black 'T' locking screw - then turn the silver lever as far as it will go clockwise, about quarter turn, the handle should be free and not turn the table at this point. Ensure the table clamps are free and whilst turning the handle re-engage the worm by turning the silver lever back as far as it will go, about a quarter turn again. Lock the black 'T' screw.
If this doesn't help the position of the silver lever can be adjusted.
Mine has two grub screws to the right side of the handle in the main casting - one on top of the other in the same hole!.
Remove the top screw then you may need to use a magnet to extract a ball between the two. To get a closer mesh turn the inner screw anticlockwise a little and repeat the above procedure.
Replace the ball and lock screw.
Axial play of the worm screw can also be a problem this (on my RT) is adjusted by a nut locked with a grub screw behind the handle.
My backlash is 2 (points).
Yours, whilst it seems a lot it is only 30 arc minutes - that's .035" right at the edge of an 8" table, if you always turn the same way and lock the table before machining it may not be a problem, but I think you could get it a lot better with a bit of adjustment.
Of course yours may be different but I hope this helps

Steve.