With Rolig's help (thanks so much Rolig!!) I worked out what's happening - seems it's due to the construction of my home. The home builder tells me the following:
"It's caused by using large sculpts, sl limits dont allow to rezz "inside" the virtual sculptbox, it pushes the rezzed items outside that virtual box, best it to rezz the item outside and drag it in"
I then enquired about why I am able to rezz pose balls from furniture inside my home, and the reply was:
"This is about the limits in sl and the viewers, i think it let you rezz on poseballs because these are small normal prims within the virtual sculpted box or because these prims contains scripts to sit on"
So overall, it's nothing to do with my land permissions, but the configuration of my home. To be honest, it's not a huge problem for me as I will change the furniture rarely, and when I want to rezz clothes boxes etc to unpack them I will do so on my front deck overlooking my private beach, and with all the privacy I need from my security system and land privacy setting *giggle*
But for others, if you're having trouble rezzing clothes in your bedroom, try outdoors and you might find the problem is your home and not your land permissions!