Most probably linkage from gear stick toward gear box is loose and rattling. You can not see it from above, but you would need to check from below the car. If you have an option to jack the car up safely you can look the linkage from the gear stick and tighten it.

 

My gear stick is also a little loose and has a little bit of a "sloppy feeling". Is it as simple as to just put my car on a lift and then tighten up something from under the car? What is it that I should tighten up, how do I spot it and how much should I tighten it up? Thanks

 

My actual gear knob is the cause of my rattle. When you remove the knob you can actually shake it and feel the inner sleeve moving. This is what is causing it for me.

 

Is it a "facelift" - after 2003? They suffer from disintegrated bush at the bottom of the gear lever.

 

Here you can see how it looks from under side. You will see what could be loose when you move the gear stick. It could be bolts or linkage itself.

I checked and torque wrench setting gives this info: Gear selector mounting to body bolts ............ 22 Nm

 

mines a 2004 1.4 zr and has a rattly lever, what type will it be?

 

Some solutions here http://forums.mg-rover.org/showthread.php?t=493289

My self amalgamating tape fix is still doing fine

 

Dark Ice Designs have designed their own bush for the IB5 sloppiness

http://www.darkicedesigns.com/en/transmission-upgrades/61-ib5.html