Unbeknown to me, she'd been in touch with the proprieter, Tom, and he'd designed and built a "landscape" version that was perfect for what I wanted. Once he was happy with the design, Colette purchased one as a surprise pressie!!
I dry assembled it first to get the idea of how it went together (it comes with instructions) and once happy, PVA'd it all together in no more than 10 mins. Left it to set overnight before I fix it to the wall. I glued a strip of mdf to the back (some of the packing material) and then drilled this to allow a couple of screws to support the rack against the wall.
There we are, finished. All my Vallejo paints and washes in the rack, some GW washes on the top. Very pleased.