If your boot is full of dust check for places it could be getting in. Like the plugs in the wheel well, boot seal, seals around your tail lights, seals around your rear vents and maybe even the black fireproofing sheet behind the back seat. (If its there)
Jason KE30 is sending me something. Can you get the buckle to him to place inside the parcel??
As for the antenna, is there any sign showing that you previously had an antenna on your "A" pillar??
And why did you have early KE30 seats with an early buckle??
I'm keen to know what else it may have.