I've been gone a little while as I'm busy packing up to move to Austria so sorry for missing all these responses. I'm glad to see lots of swapping possibly going on.
Re: shipping xenia, I've had success of putting them into sealable plastic jars and filling with water but leaving a little at the top. If it's cold I put a heat pad in the package. When shipping with Royal Mail you have to use their 24 hour Guaranteed because 1st class doesn't mean it will arrive the next day. I've learnt this hard way. Hope that helps.
As I'm moving to Austria, and planning on taking my tank, I've got around 6/8 large bits of live rock to pass on if anyone interested. Hubby has said I can't take it all because the weight would be to much with everything else that needs to fit into the car :-( Some are covered with pink Coraline and a couple a lot of Pulsing Xenia growing on them and some have been at the bottom of my rock pile :-) If you local even better, I'm based in Camberley GU16.
Let me know.